I think everybody on here is constantly keeping an eye out for what to host next. Sometimes you spinup something which chugs along nicely but sometimes you find out you’ve been missing out.
For me it’s not very refreshing or new: Paperless-ngx. Never thought I would add all my administration to it. But it’s great. I probably can’t find the thing I need, but I should have a record of every mail or letter I’ve gotten. Close second is Wanderer. But I would like to have a little bit more features like adding recorded routes to view speed and compare with previous walks. But that’s not what it is intended for.
What is that service for you?
The way you would do this with paperless is to create a user in paperless for your accountant to login to.
You would then grant that user permission to view/edit either: a tag, a storage path, a document type, a correspondent, or just individual documents. (or any/all of the above).
When it comes to providing external share links that anyone can use; you can only share single files at a time in paperless. If that’s what you’re looking for, I’d recommend FileBrowser. You can create a permanent share link that allows anyone that views it to view the contents of a folder and download each file or the whole collection as a .zip. You can even add a password required to view the page if you like.