I've never heard of an individual union member negotiating a higher individual wage or benefits than what's negotiated by the union. My cursory google search results say the same. Do you have examples of this?
The entire point of being in a union is for collective bargaining power. What incentive would an employer have to bargain with individuals directly, only to then get raked over the coals by the union for everyone else too?
Treating you special is a liability for the employer when dealing with unions.
When you joined a union you stopped being an individual and you became part of the collective union. That's what you signed up for... and these are the consequences of that decision.