Unions don't ask for dues just to grift you. At a minimum, any half-competent union should be able to tell you how they're going to get you more than your dues in value from the union. This could be actual increased pay, benefits, or other value from collective organization.

No one is trying to steal anything from you. Unions are for workers. If you think Amazon is in your corner more than a union would be, I would consider reevaluating that idea.\

All that said: almost no unionized workplace that I know of has a situation where you are required to be part of the union to work there, so no, you won't be forced. For example, U.S. federal employees have huge, long-lived unions with a lot of prominence, and only 26% of federal employees actually belong to a union.