NC app 33.0.5, Tahoe 26.5.1. No sharing options, no Finder integration. Restarted, no dice. No change on my part whatsoever.
Any tips? Thanks!
Assuming you are using the classic synchronization folders, please note this known issue:
This is a known problem and we have not figured out yet how far we can influence macOS to behave as desired and load the FinderSync extension which conflicts with the file provider extension (a problem handed to us by Apple which considers file providers the designated successors to those legacy extensions and does not allow both running simultaneously while macOS has the sole power of choosing what is loaded).
that URL doesnât exist. Thanks for the answer, but I donât know what it actually means - does this mean Finder integration is not present at the moment? Because in my case, it isnât. No trace of it.
I am sorry, we had to restructure that part a bit to reflect the correct terminology, hence the link broke. I updated the URL in my previous post. 
In summary it means: It is not possible to have the classic sync folder integration and a file provider set up at once. The latter will always be preferred by macOS.
I am currently working on improvements in the user interface and experience which makes this more obvious and explicit. They will make it into 34.0.0. Also, I am working on FinderSync loading improvements which should ship equally. Hopefully we can nudge macOS into a more reliable extension loading behavior but ultimately it is not under our control.