These days you might as well just use 7-hydroxymitragynine, mitragynine pseudoindoxyl, or speciociliatine (kratom chemicals).
I'd be wary about recommending kratom to people when coming from no opiate habit. At least when doing so give them a strong
warning like any other chemical which has abuse potential warrants like the oxycodon the OP acquired. Kratom doesn't have the same tendency to cause opioid-induced respiratory depression and thus doesn't get the loud negative optics that come with overdose deaths. It is an opiate and has abuse / dependency potential. I don't think kratom is bad or evil, nor any chemical for that matter, but depending on that persons physiology, and their life circumstances, it could be a recipe for an addiction in itself or a gateway from it to stronger opiates. I could see it being used in the opposite direction to get people off a stronger opiate to minimize the withdrawal symptoms. I have only heard that in passing and can't speak on it at all though.
My story with kratom was when my mom passed I got drinking beer and hard alcohol more and more frequently without really noticing as an unhealthy way of coping. I get wicked hangovers from alcohol though, so got to where I'd drink four times a week at night and be miserably hung over for the other three days until midday to sometimes late afternoon. I never understood the folks who could drink more while in a hang over. Didn't want to do anymore every time I'd lose a day to a miserable hangover but also found myself in a cycle where I just kept buying more alcohol. Every grocery store here carries beer and wine and has a liquor store in the parking lot which I always found myself down that aisle. That lasted through the first year of COVID since I really had nothing else healthy to get out of the house to do nor socialize to break out of that cycle.
I tried kratom due to a friend saying how much it was helping him. He used it in the low does for the stimulant effects and it helped him with depression and energy levels. I didn't really get the low dose effect benefits like my friend but did feel the higher dose opiate effects. At the beginning I’d take a couple grams and it'd have strong effects. Then I'd eventually dose it couple times a day. Then tolerance sets in quick and your at three grams each dose then you add another dose per day.
I did end up quitting alcohol successfully by replacing with kratom. The stereotypical trade one addiction for another though kratom in my eyes was better at the time as I wasn't losing half my week to hangovers and had minimal negative side effects besides it plugging you up. At least minimal in the beginning. Being a morning coffee drinker I found it nullified that primary negative. I used kratom for the next couple years.
When I finally decided to quit, my first dose of the day was usually 15g then would take 10g redoses several times per day. Got to where really no matter how much kratom I took I didn't have a felt effect from it. You hit the point you try to take more to get any felt affect, its too much for the body to process, and it makes you throw up. So your doing the same exercise as any other eventual daily opiate user where you take it just to avoid the withdrawal.
Mentally I felt like I'd probably just do it forever. Thought about quitting each time I went to buy more and told myself more than a few times the next batch I bought would be the batch I quit. Just like alcohol I observed the pointless cycle I was in, yet kept it going long after I knew it overstayed its welcome. Another false justification of it not being a problem is that you can hide it successfully from everyone, work full time while performing great, and nobody close to you notices any large difference physically or behaviorally. I was tethered to it though, all while hiding it from everyone. Since I was hiding it I couldn't travel with family or friends if it meant going out of state or shared lodging for extended periods without somehow maintaining the dirty secret. Having people stay at my house was the same juggling act. If I had to do an all day event I'd figure out some way to accomplish my typical redose(s) while not at home but also in secret.
One of the worrying physical side effects arose after a year in or so and was that it made me have to pee often during the day and even worse at night. I'd wake up four times a night wide awake and I'd just lay there awake until I urinated. I'd get myself out of bed to pee for a few seconds with nothing of any quantity came out to justify the body waking me up nor getting my ass out of bed. I assumed and worried that'd be a permanent side effect assuming I screwed up my bladder.
Not sure what actually kicked my ass this particular week but started a taper where I reduced 10% first day, 10% the next, and did that four days in a row then quit cold turkey. When you look up taper protocols people usually slowly taper over several weeks to a month. With how much I was taking I didn't think I'd actually quit with a month long taper. Figured I'd probably not thoroughly track doses everyday and wind up dosing more times and nullify the taper. Last day I dosed was the Friday I started the four day taper.
By midday that Saturday I had felt withdrawal symptoms. Sense of taste and smell was off, food was putrid, and going out for a walk the air had an off putting scent everywhere I went. I'd get too cold and cover up with a blanket then shortly after be too hot. General discomfort in my body resulting in tossing and turning. One side effect I didn't hate was I got rolling goosebumps like you get when music or an emotional story hits you to the core. Those goosebumps could start at the feet and go up the leg and stop, start at the head and go down the back, start at the head and go down both arms and both feet, or any potential combination. This I actually enjoyed in the midst of all the other side effects. I didn't really have desire to eat much for five days straight. Worst side effect was that all night when I tried to sleep the hot cold cycle kept me from sleeping. I slept about five hours from that Saturday when I woke up until the next Friday when I crashed six days later. I laid in bed each night with no light and no sound trying to sleep for nine to twelve hours and only had a couple hour long spurts in every other night where I knew I slept from having a dream. I tried sleep aids which had no effect. I tried a couple strong indica strains to help with sleep which I know have that effect on me and those also didn't really have much effect at all.
For about ten to twelve weeks after the withdrawal ended my sleep cycle was a wreck and abnormal from what it usually is. I continued to have no felt effect from sleep aids such as melatonin or benedryl during this period as well as an insensitivity to other substances such as THC. Benedryl historically made me drowsy the next day and would at least make me feel sleepy a few hours after taking. This sleep cycle change and insensitivity to sleep aids, was rough since I worked full time through quitting. I believe my body was in shock from the lack of the dopamine and serotonin cycle the kratom caused my brain to produce and was forced to normalize a routine without. Thankfully the kratom bladder side effect went away entirely after a couple weeks. I can't say I did no damage without doing some testing with a doctor which I intend to discuss during my next annual.
My withdrawal experience, I can only assume, was mild in comparison to harder street drugs common today but, again I assume, stronger and longer duration than a mild short term kratom user. The other irony was once I quit I've not had any recurring nor intrusive urges to take kratom. One of the reasons why when I was using kratom that'd I'd assumed I'd do it forever was the thought of breaking the cycle, the withdrawal, and then the assumed perpetual intrusive urges.
Kratom didn't destroy my life, put me on the streets, or chew through my savings though I do feel lucky to not have considered nor escalated to stronger opiates and to not have any urges to return after quitting. Figured I'd share. My friend used it responsibly for a long time with great benefit to him.