I don't own the business. I'm working for someone else. What could I write off besides mileage and healthcare? My wife doesn't work if that matters
Well... let me help you be creative. If you drive and want to feel safe while doing so, how about buying personal "security equipment", training to use said equipment (range time, ammo, etc.), clothes/footwear/safety equipment, cost of a business computer, etc., plus a prorated amount for cell phone.
Any start-up costs? Did this line of work include a business investment? Did you consider starting an LLC, invoicing the business you work for as an LLC, with payments to the LLC, and have your wife be a 50% owner? If so, pay yourself a smaller earned income and pay her quarterly as unearned investment income (passive income) if she doesn't actually participate in running the business. No self-employment tax on her passive income and that alone could cut the self-employment tax in half.
Not offering legal or professional advice... just a few random thoughts to get you started.