Yeah, there are still RC vendors selling 5-MeO-DMT. They are hard to find, but they are there.
The fact that 5-MeO-DMT is an analog of DMT, means you can already get busted for it if someone wants to get you for it. But as it is right now, they'd have to prove you had it for human use, otherwise they can't do anything to you in the USA. With this new change, they could get you even if you weren't using it for human use, that's all. It's a minor change. It means RC vendors cannot sell it even for non-human use, so it effectively removes it from the RC market. But there are so few actual RC vendors selling it that it will hardly make a dent at all. Most RC vendors already don't carry it.
It makes a little tiny difference, and for SWIM, it doesn't matter at all because the plant sources are healthier, and cheaper. I just don't see the reason to buy it in pure form. It's very pricey.
With such a change the DEA will make such a tiny difference that's it's honestly not even worth their time. Almost no one uses 5-MeO-DMT. Probably less that 1% of the population even knows what it is.