I can tell you what happens in this extreme case, because it’s so slow that I see it.
And I will write a separate bug report for that.
Edit: here is the BR.
What happens is this:
If I switch in a Query from a Grid View with thousands of Objects (that makes no problems) to a Gallery View with my 36 Collections, it needs 15 seconds.
During these 15 seconds I see masses of unnecessary Objects appearing in the Gallery, before they become removed, quasi “one by one” - and that need time!
That means:
The Query fills the Gallery with ALL Objects AND shows them (what’s a bit stupid btw.), only then begins the filter to do his job.
Now the filter removes the unnecessary Objects “one by one” and the Gallery becomes refreshed again and again. You can watch the Objects disappear one by one.
I know this effect well from my own programs. One could call it a “beginner’s mistake”, although I don’t want to offend someone.
Filtering and resorting should happen in the background (visual refresh paused). This saves a lot time – much more time then a SSD could save compared to a HDD btw.