A self-employed person who reports their income on SCH C as a part of their personal tax return is either a sole-proprietorship, a single member LLC or a contractor. For tax purposes, the only difference between those three is the spelling.
If your income is reported on a W-2 and the "statutory employee" box on that W-2 is not checked, then you are not self-employed for that income. Period. You don't get to chose here.
"I’m getting hammered by the cap on job related expenses in my itemized deductions this year"
What cap? There is no cap. W-2 job related expenses are just flat out not deductible at all starting in 2018. But then, maybe you're referring to a state return possibly? I can't speak for any state return.
