Scenario in short:
I’m trying to install LineageOS onto a spare phone that I have (redmi note 8T) Hoping to get a daily driver out of it. The installation process requires me to install Android11 to install lineage on top of /over that. Which afaik isn’t directly available outside of some websites that I’ve never heard of.
For safety’s sake: would the install of lineage wipe the install of Android11? Or could there still remain backdoors?


Redmi note 8T
https://wiki.lineageos.org/devices/ginkgo/install/variant2/#checking-the-correct-firmware
Thanks.
As other people people already guessed this is needed because more recent versions of the Stock OS won’t let you install a Custom rom.
After you’re done the old stock OS will be replaced fully by lineageOS.