So it seems the Mini 2 automatically switches to the H265 codec at high resolutions without the ability for the operator to choose otherwise.
In this case you have 2 options:
- Find/use a videoplayer that can handle the H265 codec.
- Convert the video to H264 with VLC: How to Convert HEVC Videos to MP4 Format in VLC Media Player? - YouTube
or google “convert H265 to H264” for other solutions.