if you want to write a ttrpg, here's my advice
- figure out what big one you want to write
- shelve that, write a small one instead
- find someone who's written a few small games to chat with about your big game
- find someone who's burnt out before releasing 3 games to chat with about your big game
- find someone who's released a game to chat with about your big game
- find someone who you perceive as big on twitter without any evidence to chat with about your small game, intimate that you have a big game in the works and be shy about it.
with all of that covered, what I actually recommend is get involved with a ttrpg community that is in the throes of playtesting. You want to meet people who are playing ttrpgs because you're going to find people who will match your freak. find a group that vibes good etc.