Lumber is very expensive lately! I'd price out every single item before I spent too much mental energy on anything with lumber, screws etc. Where I am, you can't get 12 ft studs, so just be sure. Plus, the roofing panels (plywood vs purlin supports...).
I would also explore a hoop coop. You'd need cattle panels, t-posts or other stakes, depending on how rocky your soil is, hardware cloth, and tarps and/nor shade cloth.
The birds will want (accept) something with a corner they can get into to feel secure for roosting, but you'll want to see which way the worst winds come from in the winter and be sure to protect from those winds.
Bear in mind, any pavers etc will likely eventually attract rodents and animals to eat the rodents (snakes possibly).
Another option is the walk-in poultry pen by Aleko--it's 13x10 ft but made of chicken wire. It's possible that by the time you covered the structure over with hardware cloth and predator proofed the doorway and added an apron for digging, you'd still come out ahead, and it is probably a lot less strenuous to put together than a hoop coop of cattle panels, not to mention having it delivered vs trying to haul 16 ft long cattle panels.
Third option, I did used to have a dog kennel with fencing for a top, and built a roost in it. The roost was a 4x4 structure with 1-2 sides paneled and a roof, on 2x4s and with 2x4s for the actual roost bars and structure. It had shade cloth on the leeward sides. It was completely open from the ground up to roost height, but it provided shelter and a feeling of security at night. Had I omitted the shade cloth, it would have been too open and not used. And it was in a secure structure with an apron etc.
Chickens don't like change, but it's possible that whatever you pick, you'll have to fine tune. Best of luck!
