> Most Android devices these days have bootloaders that cannot be unlocked
[citation needed]
I'm finding the majority of devices to be unlockable as long as you don't buy your device from a carrier.
Carrier locked devices are not typically the norm but in the US.
And if you truly cared about software freedom, you wouldn't be buying carrier locked devices in the first place.
I really wish people would stop griping about losing security features when you flip the one switch that ensures the security of the system. Unlocking the bootloader means it is now possible to modify system files. Of course Safetynet is going to fail. The point of Safetynet is to ensure the system hasn't been tampered with.
However, despite all of your doom and gloom posturing without actual examples, I've yet to actually use a single app (and I use several banking and root detecting apps like remote features for my car) that will prevent me from continuing to use the app if rooted. It just pops up and says "We see you're using a rooted device, this is not recommended." I click "OK" and proceed as normal.
The alternative is to use Apple and whelp, that'll never happen... since I actually do care about software freedom.