Easiest Android TV only way Or App to backup an App & APK from it to share/ export?

I need to ask a non tech extended family member to do so as I can try and sideload & run those on our TV.

Why? Mi has updated all TVs with Miracast except the 65” we have of the same series / year. There seems to be no reasonable logic to stagnated way in which they’ve pushed this update.

If it’s just not possible what would be easier way to do so that I may ask one of the younger inhabitants of that house. Ps: can’t go there.