A few things: On chess.com - I can barely only find a match with 5+0 time control. With anything else (such as 3+2, 5+2, 5+5) it just keeps searching and searching - until it says “unable to find match”
Now I just finally got into a game, and then I play my first move - and then the opponents clock starts to run… and then suddenly my clock again, but it doesn’t indicate any move from him