My understanding is German and Scandinavian unions are much more collaborative and are unlikely to force demands that bankrupt companies.
This is why unions have such a negative connotation in the US. A lot of people see municipal governments being held hostage by unions over pensions and early retirement, and union employees being so hard to fire that you end up with "rubber rooms" and end up associating unions with expensive enshittification of services.
24 states allow Union shops (workers must join the union after hire).
In theory multiple unions could strike together. Alternatively, dissenting members of a single union can keep working.
In both systems striking is the union leverage.
But that alternative of dissenting unions not striking is exactly the loss of leverage that I was talking about.