Double post I guess, and getting a little off-topic, but I missed this earlier.
As for multiplayer, I'm still not skilled enough with a wheel to have any real confidence in joining a league unless there's some dedicated beginners group or something, and meanwhile from what I can gather 90% of multiplayer is limited to GT3 cars on Spa, GT3 cars on Nurburgring, a gaggle of drift servers, and a bunch of people trying to recreate Tokyo Xtreme Racer for some reason.
There's some misconception about leagues being "esports" things or something only "pros" do and that they require a ton of free time to practice constantly, but that's not at all the case. There are a few pretty elite leagues out there of course but they are certainly not even close the majority and are generally pretty private, and yeah if you want to be "pro" you have to spend lots of time practicing, but most leagues are just a mix of players who like cars and racing and got tired of getting crashed into in public lobbies by people who don't care.
I've been doing multiplayer league type racing for almost 20 years now, and I've only ever been in one league for a sim or simcade title that didn't have at least a few beginners or people more at an "amateur" level. Particularly on the sim side of things, most leagues have more beginners than "pros" from my experience. I've seen a few that tried to be more "pro" but they never even got off the ground as most players don't fall into that category and lots of the better drivers got to where they are by being a beginner in a league so they don't like the idea of not letting people in.
Few leagues out there will care how fast you are, they just want you to race/drive clean and do your best to be safe (aka no unsafe rejoins, respect the pit exit lines, no crazy high risk moves, etc). People are quite understanding that it can be daunting and many are willing to practice with you and share advice/tricks, so you can learn much faster and have more fun while learning by playing with a group where you can just ask stuff like "what gear are you guys taking this corner in?" or you can follow them and learn their lines or where their braking point is.
Public lobby multiplayer is pretty clogged up with GT3 at Monza/Spa and AC does have a ton of (pretty toxic from my experience) drifterbros, but the leagues are mostly people who want to get away from that stuff... Although there is still is waaaaay too much GT3 for my taste. You will probably have to join a few before you find one you feel like you fit in with well, which can be kinda annoying and/or time consuming. Like any group of people, they all have their own little "culture" with some being some being more serious, some being very laid back, some very carefully and thoughtfully regulated, some that they just kinda pick stuff and race it, some that are very close-knit and some that are more open, and so on.
Just based on the fact that you are concerned about it, I can guarantee you are more competent than some drivers running leagues, so I'd recommend just going on the hunt a bit and try some out. When you find a group you enjoy racing with it makes the hunt worth it, and you will wonder why you didn't start looking sooner. It doesn't need a big commitment, just join up and run a couple of races (assuming they allow partial-season entries, which most do). If it's fun, stick around, but if it doesn't feel like your crowd, move on. Many of the people running in them also run in other ones, so they might be able to direct you to another one to try.