Here's a solution that will most probably work for every Android phone (Android 2.3.3 and up):

Go to your system settings. Find "about phone", "info", "about" or "system info". Find the build number of your device and tap 7 times on it. You should see a succes 'toast' popping up.

Go back to the main screen of the system settings and enter the new "Developer options" menu. Scroll down (a lot) until you see the "Transition animation scale" option. Tap it and select a speed (where 1.0× is normal, 0.5× is fast and 10× is extremely slow). You can also choose to turn the animation off.

If it still responds slowly, make sure you don't leave apps open, you clean up your storage and RAM often and "Rotation lock" is NOT turned on 🤣