It's unsurprising that the information is version dependent, since the manufacturer will be doing everything in their power to prevent their hardware being used for purposes other than envisioned by their marketing team.

The basic process is to determine if the version you have has been modified by the community and then if it is, collect the information specific to your version.

It's non trivial because not everyone takes copious notes or uses the same methods or processes as anyone else.

You'll likely find contradictory information and search engine search results have likely been affected by DMCA takedown notices.

In other words, YMMV.

The alternative is to buy something that is already open source and intended to be modified, like a raspberry pi for example.

I just solved this problem yesterday. Get a pi or nuc instead and install osmc. Its way better.

You could more than likely remove apps through adb and then replace the launcher with one of the 3rd party launchers on android TV like lean back on fire or projectivity.

We have a standard 4K stick and yesterday I looked into replacing the launcher. Unfortunately it seems that Amazon have stopped users from accessing ADB or an ADB shell making it almost impossible to customise it. It may still be root-able but I wasn't that desperate to change it.

Don’t update it and wait for the community to crack it. The newest firmware almost always has vulnerabilities patched from the previous firmware.

Hmm not good. Was thinking of getting a fire stick but assuming I could flash ROM from xda.

Just ditch this proprietary crap altogether and get a torrenting setup with Jellyfin or Kodi media server