If anything a union would aid job mobility. And theres no reason you cant still individually negotiate and receive equity if you are in a union.
IIRC union seniority is tied to the current employer. Move to another employer and all your seniority and the perks that go with it are gone so union members avoid it. No mobility for you.
IIRC union seniority is tied to the current employer. Move to another employer and all your seniority and the perks that go with it are gone so union members avoid it. No mobility for you.