OS Catalina - How to organize Audible books - where are my tags?

I have over 1400 Audible books and had these heavily tagged, renamed and customized in my iTunes library. This allowed me to read (listen to) series books in order, listen by *my* favorite narrators (not someone else’s popular readers), correctly define the year the original book was published (rather than the year it was added to Audible), cluster titles by my own categories - and many other organizing options. In Catalina, these books are just dumped into one big folder.

I’m curious. Where are my tags? Are they completely wiped out, with no hope of retrieval? Or is there any hope these still exist somewhere and will be re-incorporated at some point?

Finally, will I have the ability to add tags in the future - or at least customize the inane and duplicated categories currently set for my audiobooks?