~~Just wondering if the flatpak is an official package by the devs or by a third party. I'm unable to sync until the flatpak updates to 3.7.0+ and the last update to the flatpak was a couple of months ago. ~~

Edit: Never mind. Found my answer here. Didn't find it at first because I was looking at the Joplin Github issues page and not the specific Flatpak Github issue page.

Carry on. I'm an idiot.