I think the Note Attachments window (Tools > Note Attachments) has a lot of potential. I'm wondering if there could be a column that indicates where an attachment is used/linked? This could be a nice way to find orphaned attachments. A sortable column/search feature would also be excellent. What do you think?
You can now use joplin-batch-web to check and clean up unused attachments
Yes, but I too prefer the idea to do all of this locally.
In fact, this website works purely locally, you can verify this by checking network requests or viewing the source code through devtool