a bit expensive (one I looked at was $50), but depending, might be worth it.
Years ago, when living in Rochester, MN, often, after work on Fridays, I would do the 6 hour drive to Bayfield, WI to paddle the Apostles for the weekend.
Typically, after about 4 or 5 hours I would get too tired to continue driving and would pull over to a wayside along the road to sleep.
It didn’t take me long to realize I needed something like the above product (northern WI, summer, open car window, me sleeping = lot of well fed mosquitoes)
I made my own - sewing a long ‘strip’ magnet to a piece of mosquito netting. Worked well.
My clever mom made pop in rigid screens for the windows of our old 1955 Chevy wagon so the family could go camping in it. She got the kits (that you can still buy in big box building supply places and bigger hardware stores) with the grooved metal frame strips and splined the netting into them. We would pop the screens in the rolled down window and fold down the back seats (ah, the wonderful days when wagons actually folded down flat). Mom and dad would sleep on air mattresses in the back and dad had made a wooden bridge that went over their feet – my little sister’s crib mattress went on that and she slept there while I stretched my 6 year old self out on the front bench seat with my feet under the steering wheel.
If you can make a custom kayak cockpit cover for $4 I’m thinking you have the skills to make custom screens for vehicles. According to the original link I think they want $125 for a screen for the rectangular rear window on my 4Runner. I’d be happy to send you the dimensions and $10.