Firstly, this may not work for everyone, but I have used this trick daily for months and it has worked 98% of the time.

If your game freezes, just pull down from the top corner of your screen (or however else you access it) to access Control Center for 1 or 2 seconds

Return from Control Center back to the game. This will fix the lag most of the time after a couple of seconds in the game.

I’m not sure why this works, but I’m guessing it basically refreshes your connection to the server. Tell me if it works for you!