Companion app: option to use external player

Hi all,
I’ve been thinking on how to be able to watch my media without exposing NAS to the internet , but using home assistant media folder.
It’s already possible to watch mp4 files on companion app both on local and external network (I use Tor+keys for external address). The problem is that most browsers and webviews do not allow playing media formats like mkv or avi. To surpass this issue, you can download the file and open it with other apps. But, in my ignorant opinion, companion app could have an option to “Use external player” to play media.
This would bypass browser limitations and avoid the need for downloading files before playing them.
Is this possible in the first place?
Is it worth trying to develop such a modified companion app?
How difficult would it be?
Thanks in advance for patience