Welcome to the community!
There are a few important differences between tabletop roleplaying and the roleplaying people do here.
I know it's obvious, but this is much more collaborative creative writing and tandem stories than playing a game. Plots are often undefined and open if they exist at all, where in a tabletop roleplaying game an adventure is set out and it has explicit goals. What people here call a plot is really more like a premise rather than a rough plan of a story's events.
There usually aren't any rules. People have widely varying ideas about what's appropriate, acceptable, or good form. In one group story, I was in a scene with another character, and another character suddenly appeared from across the city to participate in the scene. Look for writing partners who are compatible with what you think is good form.
Stories frequently peter out or go silent. While it's a drag, it happens a lot, so don't be concerned about it. Just keep going until you find a good long term story.
I'd suggest creating a Request Thread about your interests and the stories you'd like to write about, and then discussing ideas with people who respond. Another thing to do is read other people's request threads and then message them if you like their ideas.
https://writerssanctum.com/forums/roleplay-request-threads.23/
Here's the section for playing D&D and other tabletop games on the forum. The staff is very friendly, and they'll be happy to tell you about how to best set up a tabletop game for forum play. I've played tabletop roleplaying games on other sites, and it's not that hard.
https://writerssanctum.com/forums/tabletop-legends.119/
Anyway, I come from a tabletop roleplaying background too, and this is a great place to keep up your roleplaying while you can't get a group together to game in person.
