What happens to your save files if you delete a game from ps5? Do you have to backup them before deleting the game or they are stored and will be avaible whenever you re-download a game?
Save files are stored separately from game data. Deleting a game shouldn't affect any save data. When you manage storage you will see them clearly separated.
They should still be there, but it might say something like unrecognized save data if the game isn't installed, and will re-recognize it when you reinstall the game.
Like already mentioned, saves don't get deleted when you delete a game. They are still in your system storage. So if you need to make space on your drive, don't worry about deleting and redownloading later. Your game will still be intact and you can continue where you left off.
If you have a PS Plus subscription, saves are also uploaded to the cloud.
You can also manually back them up to a flash drive.