So I finally found a way to install the stock Android TV launcher on Google TV. It's fairly simple.
First you'll need an app called "App Cloner" version 2.4.9 — I would link it but everytime I post a link to an app reddit deletes my post. The app you're looking for has a dark blue background with a white DNA icon.
Install in to your TV via sideload. On your TV, go to play store and search for either Leanback Launcher (Android TV Launcher) or Android TV Home. If you choose to use Android TV Home you'll also need Android TV Core Services.
Once all three of those apps are installed, open App Cloner. Find "Android TV Home/Launcher" and Clone it. Install the cloned app and you're done. You now have Android TV back. Or Leanback if that's what you chose.
Things that dont work so far:
No ads at top of screen, Channels row missing, holding home doesnt open app drawer