I’m from a union family and was in one myself for many years before I changed to a career path where it’s proven difficult to organize. You’re starting in a good place, but few points.

• The members are the ones who typically determine union leadership. If the union isn’t doing anything, it’s probably… at least partially the members fault. However, just like in the real world, the wants and needs of older members tend to dominate (as turnout of older members is generally higher) and that can leave newer members left out.
• You might not get everything, but you typically will benefit from most of the things the union fights for whether you’re in it or not, so for voluntary dues you end up in a situation where the smartest short term play is to not be in the union so that you can reap the rewards without having to contribute. However, this leads to the union not having the funds needed to fight for more things (because not enough are contributing).
• Having unions funded by the corporations directly is slippery… It’s like going to court and your lawyers are on the payroll for the other side. It creates an incentive to side with the people who are funding them.

You have to remember that… a business treating you fairly would ideally be the default, but there’s no reason they have to. Your union should be watching out for that for you so that you can focus on showing up and doing your job. The dues aren’t for “getting benefits”, you already deserve those and those already should be owed to you, the dues are for having someone to fight for you and advocate on the behalf of you and your colleagues.