I want to install my own software on my smartphone. However, I don't want others with physical access to be able to do this... here we hit a problem, because if the device allows extracting the data, bruteforce becomes feasible..

Also I don't want others to be able to use my phone after stealing it.. here FRP lock helps me but in order for it to work it must also limit how I can use the phone.

I wish we stopped falling for this technical trap and finally focus on the substance - hardware/software companies get away with anti-user features that run on the user's device. This shouldn't be allowed.

I don't need an unlocked bootloader, I just don't want the preinstalled Google spyware. Google should not be allowed to hold my device hostage like this.

Yes, that is exactly what the author is saying, wanting government regulation. For one, the government won't simply say "keep the device open for the end user" (or a "smart" government wouldn't), but even if they did, you've now opened that device to any attacker, law enforcement included.