UI 6 update: MkV files not showing gallery anymore

[Baido]

After the recent one UI 6 update, The .mkv files are no longer recognized in my s23 ultra anymore. Please help. 

[Samsung_specialist]

We would like to apologize for the issue you're facing after the last update. However, we kindly advise you to install any mp4 player from Google playstore.

[Baido]

Its not just recognising the files, any mp4 player or mp4 videos are lagging when casting or when mirroring my phone on a bigger screen.