I’m not quite sure what your complaint is. If you are a “contractor” you already have the ability to negotiate pay and conditions where you work. That is the definition of contract. Bernie’s Medicare4All would make sure you have healthcare, which has to be a huuuuge benefit for anyone who gets their coverage from Obamacare. Also, if those you contract with are employers as well, they will have a huuuuuge savings that you will probably benefit from as well.
It’s been proven that unions raise standards in wages and working conditions, as well as benefits, for even non-union workers. If there are traditional employee positions available in the field you contract for it’s a simple matter of taking one of those, likely at an increased wage or making the “choice” to remain in the contract position. Either way, you’re sure to benefit from fewer unemployed workers to compete against you and the higher wage standards.