In A12 kernels needs special stuff to boot. So do not change kernel. You can switch to kernels with A12 support.
If you face screen flickers (You won't mostly). Don't panic... It will go away as you use the phone
Music from local media player is dead but PowerAmp works fine. Also Spotify , Youtuber music and other apps like Files go and telegram have no issues with audio
CTS is not passing by default, You need to use magisk to do so