I have a 2 story house where upstairs bedrooms hot in summer cold in winter. Attic insulation is good.

After chasing this issue for some time I found cold return is panned in crawlspace to the box main for return, Traced it back to brick wall for furnace room which has wall vent. I look up at ceiling I see more panning between joists going to main cold return box at furnace. I pulled started to pull down part of panelling previous owner put up they blocked off the vent in ceiling .

Can I use round duct to connect from ceiling and run through that wall and thru the panning in crawl space and connect it to the box in Crawl space ? I really dont want to use panning as any dust/dirt can collect when walking on floors above it plus is would be really sealed

any suggestions ?

thanks

rob