How to flash vanilla AOSP and root my Samsung A51 device?

Hello I have an old Samsung Galaxy A51 (SM-A515F/DSN) running on Android 13. I want to turn it into a small server, so to do so, I need to install "Linux deploy" (it needs root), but for debloating and efficiency reasons, I want to install a pure Android version, as I need no Google service. The operating system will just be the host for "Linux deploy". I know this may seem out of the scope of my question and may be the topic for the next thread but I'm just giving background information. The main question is "How to flash vanilla AOSP and root my Samsung A51 device?"