There is nothing wrong with the S23U. It's a brilliant device. It could just need a spring clean, especially if you've recently updated. In fact please ensure you have ALL the latest updates.
Try wiping the cache partition
You will need to plug into a working device or pc/laptop.
https://www.samsung.com/uk/support/mobile-devices/how-do-i-clear-the-cache-on-my-device/Also, consider reaching out to the game/app developers as they may need to make improvements to their software to make them perform better (it's not always down to the phone).
Feel free to do as you please with the phone. It's your money at the end of the day.