Unions are not a one-size-fits-all solution to worker exploitation. At best, they protect workers from the worst effects of capitalism.
Corporations spend lots of money trying to bust unions because of the threat they pose to wage theft -- with nearly $8 Billion dollars stolen from workers yearly. In other words, our bosses wants us to work more for less, stealing the surplus value. Workers take all the risk, do most of the hard work, and have the least to show for it.
Unions allow workers to get the most value out of their labor. When separated by the managerial class (bosses, CEO's) and forced to compete, workers are made to earn less than they would if they collectively bargained for fair wages and safe conditions for their work.
Links below for more information about unions.
What Is A Union? (Alki | Youtube)
Why Your Coworker Makes More Than You (Leaflets | Youtube)
How To Organize Your Workplace Without Getting Caught (Vice | Text)
Workplace Organizing (Libcom | PDF)
Unions and “Work Ethic” (Mexie | Youtube)
r/antiwork library (subreddit | Library)