Sorry, buddy, such detailed screw specifications (thread size, pitch, total length fnaf, shoulder length, head diameter, screw type) for the Bitspower Classic VGA Water Block for RTX 3090 FE are not publicly available through general searches.
This is very specific technical information from the manufacturer. The best way for you to get it is to:
Contact Bitspower Support directly: This is the most accurate source for technical drawings or screw specifications.
Check the product manual: Sometimes they list the screw types.
Ask the modding/watercooling community: Someone might have disassembled and measured them before.
This info isn't generally ******; you'll have to ask the manufacturer directly.