Cant speak on Europe, but for NA esea stopped supporting tf2 after s31 and has been replaced by a league called RGL. There's been a lot of resistance and everyone hates them because of the admins and some drama but the numbers are doing really well with the lower divs taking in a lot of new players. LANs in generally kinda died after ESEA stopped theirs, and RGLs attempt at running their own LANs was stopped by covid. I'm still pretty hopeful that RGL will start running LANs once covid settles, and RGL is also supposed to be releasing a new pug system soon (within this year most likely) which will probably do a lot to grow the lower divs.
Scouts are really powerful. Pocket scout (you heard right) has replaced pocket soldier as the "leader" of the team. Flank scout has taken a more active role and coordination between scouts and how the they capitalize on openings is what defines a lot of teams. In general, scouts have become the aggressors while soldiers set up and support the scouts. There's been some changes to the whitelist, new items, reworks, disagreements over rules, new maps, but the game is still recognizable. The main difference I noticed between old and modern demos is that the team coordination looks more mature if that makes sense. It probably wont be as bad as what you might hear, but it will be a culture shock for sure. (take this part with a grain of salt because I'm not very good and never played back then; basing most of this off watching demos and what I've heard)
b4nny made a team called Froyotech and has dominated most seasons since. A lot of good players came in and out and some releases like Overwatch cut down a lot of the top players, but there's been some good storylines and matches are still fun to watch.
b4nny seems to be the only thing keeping comp tf2 relevant with new and casual players at this point. His stream is the only significant tf2 stream and unfortunately he's been hinting quite a bit that he's looking to move away from tf2 sometime soon. He painted RGL as tf2's "only hope", which I think has some truth to it, and I think if RGL doesn't deliver with their big promises of lans and inclusive pugs then comp tf2 could stagnate and slowly fall out of relevance. It also doesn't help that Valve stuck their foot in the door and dropped a half-baked competitive matchmaking mode, but hasn't done anything significant in about 3 and a half years. It's a situation similar to Smash Melee where some people want to try and work with unresponsive devs while others want to make a full promod.
Comp tf2 is in a precarious position right now. On one hand, RGL is doing and promising a lot to grow the game with new players, but covid has stopped a lot of progress, RGL is hated by most of the established players, and Valve doesn't really seem to notice us anymore. But ultimately I'm pretty hopeful for the future of tf2 (could be blind hope for rgl though), and if you're looking to play again now is about as good as ever.