About cinnamon 4.8 these days they are preparing to put it in rc (with tags 4.8.0). Recently I did a PRs upstream for more debian patches as possible (excluding some only related to debian) and all are included for 4.8, this should help with small improvements upstream and less time to maintain them in debian (with new versions).
There was a meson porting on some other components, these need good attention to do better packaging as possible.
saw that Norbert already started prepare 4.8 packages for
experimental in git, thanks for your works Norbert, I don't
have time to check them now but if I'll time in the weekend
I'll do and I'll try to give small help.