I kinda agree that the information is highly fragmented and scattered around, but why do you want to install this rom? if you just want to get rid of some useless apps then you could use something like
https://github.com/0x192/universal-android-debloater
installing a custom rom could be an adventure that might not be as easy as you think...
you 1st need to lookup how to unlock the bootloader, if you haven't done this already then you will have to wait 7 days for it to unlock (security measure against device theft probably, I dunno)
then you need to lookup how to install ADB (Android Debug Bridge) on your computer, for Windows or whatever you have, and connect your phone to your PC, then you can test it in a terminal by typing "adb devices" and get 1 result (make sure you have USB debugging turned on in your phone)
then you need to lookup how to boot into fastboot mode and test it by typing in terminal "fastboot devices", if you installed ADB the right way then you should also see 1 result
now you have to lookup the xiaomi.eu rom version that works for you, since you're here I assume you have note 11 pro 5g or something like this, you should lookup its device codename, in this case its "veux", and compare it against the xiaomi.eu available downloads, in this case you should look for something with the name "veuxg", download it and extract the archive then double click "windows_fastboot_first_install_with_data_format.bat" (I assume you have windows) and let it run, it will take somewhere between 5 to 10 minutes to install so don't panic, after that it should reboot and you're basically done... good luck
