Thank you for your post!
After looking at the file, I would recommend moving from the Classic Theme (to Minimalist for instance) as it has been deprecated and removed from the software. This seemed to make the file a little more efficient in my testing.
I am also going to move this thread from the FileMaker Community Feedback Space, which is specifically for input on the Community itself, to the Discussions Space where others might find your post easier and offer further advice.
I hope this helps!