Yes, they do try this from time to time with an incompatible device like yours, please search the forum – it always ends in disaster.
The /e/ ROM is not compatible with relocking the bootloader in any devices where it is not mentioned in the install page.
Also see [LIST] Devices where bootloader can be relocked.
For a safetynet fix perhaps start from this page Xiaomi, faut-il rebloquer le bootloader.