User Data is huge, currently sitting at about 900 MB for me. This would be acceptable if I had lots of multimedia in my notes. However, I only have more or less 50 notes which are mostly unformatted text. I have only a handful of notes with an image or basic markdown formatting like bullet lists.
What is the reason behind this? It's abnormally large as I'm not logged in with any accounts / haven't set up sync. I'm using Joplin completely offline.
Just a guess, but it could be your note history, assuming that it's enabled, of course, and the 50 notes are older notes that have gone through many changes over time.