UAW already went through some reforms which is arguably why they're experiencing a surge in popularity. In particular Shawn Fien was part of UAWD's 1 member, 1 vote initiative: https://uawd.org/
The characterization that they would eschew reform even when it would boost their popularity is not reflected in current events (certainly the managerial friendly unions of the past would avoid reforms)
Those reforms aren't comparable to Swedish (which I'll use as a stand in for Nordic) Unions.
At the end of the day, unions in Europe are much more pro-business management than any union in the US can ever dare.
For example, Swedish unions didn't go on strike when Geely fired thousands of Swedish autoworkers when acquiring Volvo, and German (yes not Nordic) unions haven't fought for salary increases leading to German salaries remaining stagnant since the 2000s, while helping German corporations like Volkswagen, Daimler, etc remain competitive globally.
In the US, unions will go militant and remain independent of the government and management because they are grassroots driven. In Europe, unions are subordinated to the government and management, as Union leaders end up joining both.
The characterization that they would eschew reform even when it would boost their popularity is not reflected in current events (certainly the managerial friendly unions of the past would avoid reforms)