Devices that don't depend on 3rd parties to unlock bootloader?
Are there any devices that, by default/by design, allow the user to unlock the bootloader totally offline, no ransom, validation, account, internet or whatever required?
I think OEM, non-carrier OnePlus phones do (someone correct me if I'm wrong or out of date). I just setup Lineage 21 on a OnePlus Nord N200 (ca 2021) and after enabling bootloader unlock in developer settings, I just had to pass the oem unlock command to fastboot. The carrier-branded ones require you to go through the unlock code request, and those take a minimum of one week (and can be cockblocked by the carrier for whatever reason).
There may be some kind of Android check, though, because the "Allow OEM Unlock" developer option was greyed out until I connected the phone to wifi for a few minutes. Not sure what that's about, but it's common for most/all android devices. I don't know of any device that lets you unlock the bootlaoder without first enabling that in dev options.
It's definitely not a top notch phone, so don't expect it to be a powerhouse of a gaming phone or whatever, but it's actually a pretty decent phone to be fair.
It doesn't have many sensors, only the accelerometer, light, proximity, and significant motion sensors, so don't expect it to work with RFID or NFC devices either.
But where it lacks in power and features, it makes up for in an amazing battery life, plus even the stock Android ain't too damn bad. 👍