Code
2021-09-17 11:32:31.457 T:779 DEBUG <general>: [WHITELIST] whitelisted modes:
2560x1440 @ 60.000000 Hz
1920x1080 @ 50.000000 Hz
1920x1080 @ 29.970032 Hz
^ this is the original log that you posted. Set the Kodi desktop to 1080p60, then allow doubled rates, and whitelist 3840x2160 @ 30/29.97/25/24/23.976, and 1920x1080 @ 60/59.97/50/24/23.976 modes. Enable "adjust refresh" on start/stop, and check for glitchy playback again.