My wife added me to family sharing but Apple Music is still requesting that I subscribe not automatically working

If you wife does have an Apple Music Family subscription, you might be able to fix your issue by turning Sync Library off for all of your devices, then turning it back on again.  Learn how.

Also, did yo accept the invitation according to the 'Join a family group' section in:

Set up Family Sharing - Apple Support

To share Apple Music, you need Apple Music family subscription => Get an Apple Music family subscription - Apple Support

Cant even find sync library