playing 4k videos issue and equilizer missing

After the recent updates 11.7 all my old 4k videos that were working fine before are not lagging and does not responds sometime. ALso the eqilizer features has been removed. Please fix and add the equalizer function as well

Equalizer functionality has not been removed. You need to use ffdshow for that.
MPC-HC options > External Filters > Add "ffdshow audio processor" and set it as preferred. Then double-click on it to open the ffdshow settings.

Which CPU and GPU do you have? You probably need to enable hardware acceleration in the video decoder to get smooth playback.