I'm in the Canadian version of the PNW...northern Vancouver Island. We get all the rain you do plus as we are right on the coast out of the rain shadow of the Beaufort mountains.
we use a 10x10 EZ Up that fits over our hatch and sill leaves sufficient room to sit, read, watch Netflix, etc while you wait out a rain event.
If it is wind driven rain squall then I had a marine upholstery shop make me two "tarps" out of the white vinyl screen stuff they use on boats. These things knock rain down and reduce wind to a breeze. If we need to close off the third opening I just use a normal tarp.
https://www.amazon.ca/Z-UP-SR9104BL-Sierra-10-Feet/dp/B000NRPN8E
You can spend what you want on a canopy...our was around $100CAN and has lasted 7-8 years of regular use including a 3 month road trip across Canada and a month in the far north, up past the Arctic circle to the Beaufort sea (Arctic Ocean).
I've seen this asked several times in the past. Try the search bar.
Also, Maybe look into a 10x10 EZ UP that you can stake down and maybe add a tarp on the side as a wall. If thats not possible maybe look into a ceramic coating for the entire vehicle. There are also other protective coatings and wraps you can look into.