Correct pH is what does half of your work for you, so upto a point it really matters.
Vinegar makes the pH low, you need it low to get the dmt from the bark into your water as a salt phase.
pH will only go as low as 1 but the more vinegar you use, the stronger the concentrate at pH 1. A concentrate acid would take more effort to raise the pH up to 12 at base phase.
It's like a balancing act on a seesaw, if it takes 20kg to push one end down there's no real need to put 50kg on it, same with too much acid. Just use enough to push it down. I think most people lower it to about pH 2 or 3.
teks are written by people whom know what they're doing, I would ignore friends when following teks tbh and measure stuff pH included. good luck and welcome to nexus.