This is not the nicest presentation ever, but he includes a video to help make his point - but it looks like he is describing a situation very close to yours. Found with other similar explanations by searching this.
Edit, if I follow this correctly (I am not sure) but is your PC now seeing the same device with a different identity? Would this be why you must now delete some history?
I see the lock more like this. The system is proprietary; it had a verified boot; it had a lock to seal the system.
Google make claims that everyone can trust the sealed and verified system.
You have liberated it.
It is a different ball park.
Can an application modify it?
I have never thought a 9mm thick highly networked mini computer was secure.
Edit. I am in danger of starting something here on locking! If you copy the Google method and have a “signed system” you can lock the bootloader as done for example by Divestos!
The risk is always an estimate that differs according to the system but especially the person who estimates it.
To try to have a precise estimate, it is necessary to try to know as precisely as possible the studied system.
There’s no safe system, but you can try. ( a Debian daily user )