Many? I know Calyx, but what others?
Anyway, not possible to relock bootloader with eOS on OP9 and most of the other devices that are supported.
EDIT:
And today, bad news from Calyx that bootloader locking will not be possible on the oneplus devices with android 12 firmware…
https://calyxos.org/news/2022/07/06/oneplus-android-12-relock-issue/