The only way is if you're running Android 9, have it rooted (can't root this phone running Android version above 9, maybe 9.1) and there's a LineageOS rom built for the 20x. I don't think there was ever a rom built, so pretty sure you can't unless you build it.
two options: based on emui 9 unlock bootloader via ministryofsolutions and then either -
A) install openkirin custom rom, will work for sure but still stuck on android 10
B) check and see if any GSI rom might work, potentially issues or might not boot at all, but goes up to android 11/12
i plan to replace my battery in a few months, together with a new back casing to get rid of some scratches. with that, i also plan to try and unlock my BL and play around with GSI roms. with a bit of luck, one of them might boot and work android 11/12, here we come?! hahaha