[xkemp]

A union is run rather democratically. It will tend to reflect the attitudes of its membership, i. e. your coworkers. In some old industry on a downward slope, employees will tend to be older and risk-averse, and so will the union. Tech Unions will tend to be rather different.

Don't get hung up on this concept of "union". Look around the office and imagine what you and the ten people you see might want to ask from management.

It could be "no open-plan offices", or maybe it's better options for working remotely, budget for conferences, free choice of OS, whatever...