Itunes music not showing on all devices

I'm having some challenges with accessing all the music I've purchased on different apple products over the years. When I go to manage devices in music on my laptop music app I receive this odd message

pings metrics dialogIdexception messageexception_message eventTypedialog topicxp_its_mainactionUrlbuy.itunes.apple.com/WebObjects/MZFinance.woa/wo/14.6.0.1.1.3.0.5.1.1.7.1.31.3.7 mtEventTime2024-08-30 18:33:21 Etc/GMTmtTopicxp_its_main failureType customerMessageexception_message m-allowed dialog m-allowed messageYour request is temporarily unable to be processed. explanationPlease try again later. defaultButtonok okButtonStringOK initialCheckboxValue

Which looks like things are a bit wonky. I shouldn't be seeing the coding for this, for one and for the other I should be able to manage my devices that have full access to my music library that I have curated for over 20 years.

The Mac that has the majority of my music is an older iMac 27 inch and running older software and the graphics card is no longer working on it. I know I know I should say good bye to it but it's been my workhorse of a computer for years and I keep hoping it's going to actually come back to full life again.

So I guess my question is- how do I get my music libraries to sync?