Hmm i was gonna try to tell you to install the non-open version but it seems it’s no longer available in the official repos, at least i’m not finding it, it was a bit of a longshot anyway.
You shouldn’t have to and ideally do not want to use the opengl renderer in mpv though.
If you open a video with this command:
mpv --no-config --gpu-api=vulkan --vo=gpu-next --hwdec=auto-copy --fullscreen file.mp4
what happens? Obviously you need to replace file.mp4 with a valid file.