Alright without knowing more I would recommend moondeck it’s a plugin on decku loader. And you could also try reinstalling sunshine.

Do not delete them. What you can do is use cryo utilities to move them to the SD card. It’s slower but for 64gb decks it’s work it. Only delete ones for games you uninstalled you can use storage cleaner plugin on decku loader

You might try just launching big picture mode and going from there. It’s not as fast but it works great. Also Steam remote play on the SD sometimes works better than moonlight. Tip if you add a non steam game on your pc you can stream it to.