+1 for Valetudo!
I've installed it once via OTA and twice by FEL. The OTA was obviously a breeze, but FEL wasn't that bad. I just watched videos on YouTube for the disassembly and took my time doing each step. I love the UI and the fact that I can SSH into them just for the sheer coolness of it! I think one great thing about it is that it doesn't affect the software that the robot uses for all its tasks and functions (e.g. vacuuming, mopping, sensors), just that it replaced the cloud and runs it on device.
I don't see getting a cert as a bad thing. As far as "how good" that would be hard to gauge. IMO, a better way to look at it is what are the downsides of studying and getting the cert.
While I also am all for firmware swaps, just to be clear, this isn't a swap on the garage door opener itself. It's a standalone controller that you run 3 (at least) wires from it to the normal wire terminals on the opener. But hell yeah, I'd love a hardware swap on all my Google home devices.
Totally not weird. Just comparison reviews.