Hello,
the database can hold more than enough data
https://discourse.joplinapp.org/t/maximums-notebooks-notes-tags-and-databse-size/16234
Maximum database size according to Implementation Limits For SQLite is 281 terabytes.
The limit is rather dependent on the resiurcen of your computer (CPU / RAM).
When I add new tags or move notes, it takes about 1 second.
For example:
I have about 6000 notes and 1760 unique tags and this has been assigned 19325 times.
Joplin is on my office computer (i7 11700k, 64 GB RAM, m2 SSD) much faster then on my notebook (i5-8250U, 8 GB RAM, SATA SDD). When I add new tags or move notes, it takes about 1 second on the notebook.
But the speed also depends on the type of use, number of installed plug-ins, etc.
page size limit
I have few very large notes (Very much text), but mobile this was more of a problem. With the current beta editor this has become better.
But there are people here who have much more notes in joplin.