You don't have to wipe something , you said that you're with 20.10.30 ..
Just do the steps and flash the new rom..
Unless you want to do format again ..
EDIT
You have to know that after installation of 20.12.2 the new twrp will be flashed as well , after this installation you can only flash the new Thursday's update by using the twrp mentioned by
@Iain_B in previous post and you will need an OTG usb stick to flash..
If you don't have an OTG the only way to update is by the commands i said you from fastboot and by using the twrp.img 3.4.2b 0623 ..