There are a few US Solar wholesaler companies that will draft and sign engineering drawings for a roof-top permit application in most states. Some folks claim https://www.pegasussolar.com/ was inexpensive, and might be worth a call.

The problem with Home Solar is the same as with Heat exchanger installs... some installers price gouge, and simply don't care about the quality of the work.

Best of luck, if you plan to stay someplace 8+ years a 10kW Solar+battery install and heat exchanger are fine investments. We've also donated a few of those cheap FlexSolar 40W Foldable Solar panels + power-bank kits to people in remote areas, and they reported phone/VHF-Handy charging was reliable. =3