Ah. A AIO, that's crap. Then go for the ram upgrade and maybe look if you can fit a SSD.

For what it's worth, i know all about the: it looks pretty and we only use it to print, why change it. My mom has been playing solitaire on a 486 with 4mb ram and Windows 95 till 6 years ago. And, no it wasn't connected to the internet! 😅

See if you can fit another motherboard in the HP case. If that works, new motherboard, cpu and ram. Just tell them u had to change the windows version because of updated printer drivers. New pc, same case, same printer. Done!