Opponents who deliberately lose on time/abandon the game when they're losing

I am sure it has happened to everyone at least once. Just now I encountered someone who deliberately sat for 5 minutes straight in a rapid game when I was about to mate in 1, just so they could lose on time instead of from checkmate or choosing to resign. It doesn't violate anything, but I think it's fair to say that it's far from good sportsmanship.

I vaguely remember that while I was playing around with the site settings, there was some option about avoiding players if they've recently lost on time frequently? But I could not find it again. Does anyone know?

Edit: Just found it. It's the "Avoid Time-Outs" option when creating daily games. Honestly, I think something similar for rapid games would be a good thing to have too.

Stalling is bad sportsmanship and when next you play an opponent who is stalling, report them.
https://support.chess.com/article/675-what-is-stalling#:~:text=Stalling%20in%20Daily%20games%20is,tolerate%20it%20on%20our%20site!

I report again and again for what result 🙃?

Actions are being taken, even though they are not visible to you.

It can, for example, influence how players are matched.

https://support.chess.com/article/369-how-does-matching-work-in-live-chess