If you find that MX Player is no longer behaving as it should then try the custom codecs from XDA, here is a short tutorial:
https://drive.google.com/file/d/1LB1oBGppsKACqJU4zoUz0a39rwD5bFwQ/view?usp=sharing
Edit: for the U22: https://github.com/USBhost/MX_FFmpeg/releases/download/1.32.0/libffmpeg.mx.so.neon.1.32.0
Be sure to rename libffmpeg.mx.so.neon.1.32.0 to libffmpeg.mx.so.neon.1.25.0 and it will load.
https://drive.google.com/file/d/1LB1oBGppsKACqJU4zoUz0a39rwD5bFwQ/view?usp=sharing
Edit: for the U22: https://github.com/USBhost/MX_FFmpeg/releases/download/1.32.0/libffmpeg.mx.so.neon.1.32.0
Be sure to rename libffmpeg.mx.so.neon.1.32.0 to libffmpeg.mx.so.neon.1.25.0 and it will load.