Yeah using the built-in steam deck streaming has been very very poor for me. Like when it works it works great, but when it drops connection just like you. It desyncs and i lose video and it’ll stay like that for minutes.
I switched to using Moonlight and sunshine, though decky and moon deck. and that seems to work a lot better for me. When I desync, the quality temporarily drops, but the game is still playable. And it’ll usually pick itself back up within a couple seconds. Way better than the built-in streaming on Steam, and moondeck will also utilize your custom controller input profile if you have one.