This question has been asked a hundred times with the same answer : Google Play doesn't allow this kind of stuff.
The same on iOS.
What's really shocking is that a moderator doesn't know about .apk files and that some of the biggest second party stores (F-Droid/Amazon App Store) are only available through APK install. Same with video downloader/ripper/player like NewPipe and Ad-Blocker. The most played game on Android, Fortnite, is only avaiable as .apk Download from the developer Website. (because you don't have to pay google the 3% fee that way and have full control)
Obviously you have to activiate "Allow Install from unsecure sources". It has been a thing since Andoird 2.x and became really popular with Android 4.x ... and we are now at Andoird 10. Just saying...
The guys at Totem who manage to develop a decent Desktop app surely know about that. Well if you exclude the fact that you are still not able to play the vids in order unless you do a lot of ***** and drop work and some other annoying bugs & features, they seem to be at least somewhat competent & knowledgeable.