I have shrunken a APFS partition (macOS) too much lately and was still able to mount it read only using Linux and back up all stuff I needed. But that depends on how corrupted this partition is now.
Maybe you need something like Gparted live ISO in order to get to your data. Check out the Command Line Utilities on that webpage, maybe there is the savior of your data
And about the arch installation, if you want easy mode, just type "archinstall" after ArchISO has booted and your PC is connected to the internet (phone connection via USB works to get internet connection)
Oh, well I’m not quite interested in that right now, I have chosen Arch because I like the wiki and that you find so many packages in the AUR which are easy findable and installable using yay