@Xetetic
Coming in cold in the hobby these years is almost impossible, regardless of game. If you don't know anybody at all it requires LOTS of luck to just stumble into something by happenstance, and that just...doesn't happen. No matter where. No matter what tools are in place.
HOWEVER.
Use tools like this place, or staff, or -- Facebook, or Google, or -- to find people first. "I am interested in playing X on Y, I know nobody, would anyone be interested in being a contact / go to person for me? Can I play something in somebody's group that they're looking for?" -- it may not end up being a character you stick with long term or whatever, right? However, what it will do is start you from a position of knowing that you have a person (or people) that have straight out agreed to help you meet other people / etc. -- and it keeps it from being a cold start.
Will you always get a bite or whatever to reaching out like that? Nope. But these years, 'I am out of the loop and am looking for a volunteer to hook me back in' is probably the most effective thing you could do.
ETA: If you already have a specific game in mind, hop onto it, look at the wanted board, and page people up front. 'Hey I see your post wanting X, I'm interested, but caveat I'm a new player to the game and know no one, and would need a bit of extra help. What do you think?'
ETA2: Contact old friends who also quit mushing. DRAG THEM BACK KICKING AND SCREAMING. (spoiler: this is what I did.)