Welcome, rpchurch!
Thanks for using Apple Support Communities! From your post, it sounds like you're having trouble with your Safari reading lists syncing between your Apple devices. We know how useful it is to have these lists across all devices you use and we'd like to help!
To clarify, are you currently signed in with the same Apple ID on each device? Have any changes been made on your devices since this feature stopped working?
We recommend using the guidance in the following support article to further troubleshoot issues with Safari and syncing:
If your iCloud or Safari bookmarks aren’t syncing - Apple Support
Feel free to post an update for continued support.
All the best.