But also fully deductible work-related expenses, including health insurance, and ability to fully fund a solo 401k.
Are you sure health insurance is deductible? There was a time it wasn't. Either way that's peanuts compared to a benefit that covers most of your premium. Fully fund a solo 401k is also nothing special compared to a proper matching 401k. This is just a freelancing gig, and not "working at gumroad".