I had to help my sister keep her 8 year old Mac going or buy a new secondhand (cheap) machine. With the options out there and with the state of Windows, I didn't even consider it.
She's ended up with her same 8 year old Mac with Ubuntu 24.04, and I've been really impressed with how it's actually great for non-technical users these days! And works really well on old hardware.
This should give her another few years of life out of the thing without worrying about software support.
Go for tumbleweed, it's supporting wide range of architectures (including even powerpc so you can still use powerpc macs) and it's rolling release distro on top of that