I got the tools. I got the new batteries. Now wish me luck for replacing the batteries of my 20+ year old iPods. A classic gen 6 and a 3rd gen Nano.
The iPod nano 3G is open. And as expected, it has a bloated battery. But that can be fixed. It is still working, so a new battery should bring it back.
@jwildeboer question, can you upload files into that iPod from Linux?
@luisfcorreia Yes, with libipod. I don’t need it though, as I have a Mac.

@jwildeboer is that still maintained?
I tried last year from my Fedora Workstation and it wasn't recognized

(came to the conclusion that I have a very similar iPod here with a replacement battery to be replaced... 'soon')

@luisfcorreia I don’t know as I don’t use it anymore.