I’ve never tried it on a tcl tv but it was very easy on nvidia shield. You have to install an alternate launcher (super important to do this first) then use the android debugger from your desktop or laptop to disable the built in leanback launcher. After that, the first time you press the home button it will ask you to pick a new default launcher.

You can google for instructions on getting the debugger installed and running, and how to disable the launcher. Note that a lot of people say to uninstall it but I prefer to just disable.