Can you install the Google TV launcher on any TV?
I would never delete the original launcher to any device. I would only disable it.
Probably the best you can do is disable it. You pretty much have to disable it in order to load the google tv launcher instead.
Some version of the original launcher is in rom, and that can't be uninstalled because it is likely contained in a read-only file system. The original launcher probably has some updates installed, and you can uninstall those, but the rom version will remain.
Of course, if you've modified the rom in question, and have verity/vbmeta disabled with an unlocked booloader, then maybe you can totally get rid of it if you know what you're doing. But this offers no real advantage to just disabling the original android tv launcher.
I would never delete the launcher that came on my device unless you know a way of getting it back.
I know some phones will reinstall their default launcher when you update the OS. I almost expect the same behavior on Android TV devices. Best to try disabling it and clearing all data before you delete it.