prisi I wouldn't disable OEM unlocking, if you disable it then yes, the only way to unlock the bootloader is to enable OEM unlocking again
However, the only way this would be a real issue if both recovery and your OS have been corrupted, not likely
Repairing the operating system can be done in recovery mode, without unlocking the bootloader. You can access fastboot, enter recovery, open the recovery menu, select 'update over ABD' and use a computer to push the update to the phone (this also does NOT wipe user data since you don't have to unlock the bootloader)
This is also how you update your phone if you can't use the updater, such as if your phone never has internet
You can also use it to wipe your phone in case you forget your pin/password, the menu has an option to erase user data and doesn't require your pin to do so. Resets your phone to how it is when it was first flashed