Discord RP is superb for 1x1s or really small groups. Like [@TGM] said, it's all about the people in the thing, but I find that it being a chat platform "allows" for more variance in post length, which I massively prefer. Not every post needs to be long, and when doing dialogue with a 1x1 partner, discord RP's use of message exchanges really makes things flow well.

Post length reqs or whatnot are a non-issue if you curate your group well.

Also, I never understood why people thing the character limit is an issue. Long posts can be split up into multiple messages, just use a new message like paragraph break (WHICH YOU SHOULD BE DOING ANYWAY IN A LONG POST)