Yeah some apps but not all do require EmbyPremiere I believe.
There is “possibly” another free option and that’s Jellyfin. It’s an open source port of Emby.
It is I believe still developing at pace and as far as I know actually still uses the native Emby apps until they get around to replacing them with their own. They may already have their own apps for some clients. It’s just something I never looked into as I long since bought EmbyPremiere.
Failing that you could do a monthly Emby sub. Try it out and then balance out if the cost of the lifetime outweighs the need for an HTPC app.
Sadly there is no perfect answer.
Also your original post did mention EmbyPremiere. It’s gone now but @flow did quote it while it was there. Sorry if you feel I misled you. I just assumed that your original mention of it as a replacement meant it wasn’t a deal breaker.