If @daedaefedo is using the Gyan essentials build version 7.0 then that has a problem.
The incorporated ffmpeg in krita 5.2.2 as noted by @sooz can be used.
Or the previous Gyan 6.1.1 essentials build can be use as noted here:
Krita could not redner animation: unknown error ffmpeg - #2 by Michelist