Is this the same as the Joplin Server? (I could maybe install it on my Synology NAS)
My large amount of data comes up often. I think the first thing to do is to reduce that, as I talked about here.
I'm also reading posts talking about plugins that can slow down Joplin, and I have quite a few:
My Plugins
Backup: 1.4.0
Bidirectional Links: 0.1.2
Favorites: 1.3.2
History Panel: 1.0.2
Joplin DDDot: 0.4.2
Menu items, Shortcuts, Toolbar icons: 1.1.0
Note list and sidebar toggle buttons: 1.0.3
Note overview: 1.7.1
Note Tabs: 1.4.0
Outline: 1.5.13
Quick Links: 1.3.2
Reset Checkboxes: 1.0.1
Rich Markdown: 0.14.1