This, or we could have dual booting that's relatively as easy to do on mobile as it is on PCs.
Currently, you'd have to do find an unlocked phone, hope there is a downloadable factory image, re-flash, re-lock, re-install to run whatever needs attestation. Potentially using something like Android's DSU feature, this could all be a click or two, and you could be back running Lineage with a restart.
I mean... no thanks? I remember dual-booting Windows and Linux (and macOS and Linux) for years back in the 00s, and it was inconvenient and annoying. I don't want to go back to that, even (especially?) on a phone.
Dual booting isn't so bad, I've almost always had a gaming partition somewhere, while my current install doesn't even run 32-bit binaries. That said, attestation should be possible with user-locked bootloaders, not just vender-locked bootloaders. I suppose Magisk provides something close to this currently with bootloaders that can't be re-locked for custom roms, so more power to it.
Currently, you'd have to do find an unlocked phone, hope there is a downloadable factory image, re-flash, re-lock, re-install to run whatever needs attestation. Potentially using something like Android's DSU feature, this could all be a click or two, and you could be back running Lineage with a restart.