Can someone actually explain meth to me?

I've gone my entire gay life without doing meth or even knowingly being around it. I've been a vodka gay, a tequila gay, a weed gay, a wine gay, occasionally coke off an erect penis, but never a Tina gay. Lately (in my 40s) I've been speaking to multiple guys who admit to being casual meth users, and have invited me to smoke with them. I'll admit, it sounds fucking hot and I'm considering it, but I really have no idea what I'm getting into.

I also really like one guy and would consider dating him..he smokes occasionally. Is that a red flag? A generation ago, I get that meth and pnp were correlated to a higher transmission of STIs, but in an age of PreP and Doxy are these still the same concerns?

Guys who have tried it - did you enjoy it? Regret it? Did it open a Pandora's box of bad decisions? Can you do it occasionally without becoming addicted and fucking up your life? And seriously - what does it actually feel like? Is dating a meth user actually problematic? Like seriously, I feel really innocent here and would love someone to break it down for me. Pros, cons, whatever.

Thanks as always.