Can you post it? I did find some weird ones in the past - like if your pulldata references a field that is in a repeat that is slow.
I have 100s of questions also. I also load a 5-6000 long species list 12 times per repeat on a 50 repeat. It can take 22 seconds to open on a regular android. My iPad Pro does it on 1.6 seconds. So device is important info also.
Overall thought that is a huge form. We break our process up into 9 forms to reduce load time and be easier to read and use. Also then we can have 2 crew members at the same time.
Hopefully you can post it.