Unions are not magic. I have a friend who did belong to the local sheetmetal workers union and she was... not positive. Moved into a non-union shop and was a lot happier.
Similar experience here. Family member went into a union job and discovered that it was great for the old guys at the top who had been there for 3 decades, but it was rather repressive for the new people starting at the bottom. Much easier to pivot into a different job where union seniority wasn’t the defining factor of your entire career.
Sure, but a union is supposed to work better, so if it isn't, by definition it's to some degree corrupted. So it's important to remember that the union itself isn't a bad thing.
A union is supposed to provide for workers in the same way that a software company makes software. If either of them don't, there's something fundamentally corrupt about each org, not with the concept.