My rule for apps for sexting for free now is simple: check how the chat behaves on a weak connection on day one.
Two of us compared notes on the platform and landed in the same place on what the platform can see that you can't.
Where the room works it works fast; where it does not, whether the algorithm is doing anything useful is usually the reason.
The gap between good and bad platforms here is how quickly you can narrow a list down.
Worth comparing against what Rendate does with filters before you commit to anything.