I'm not necessarily opposed to unionization in general but it's never going to save many US software industry jobs. If a unionization drive succeeds at some big tech company then the workers might do well for a few years. But inevitably a non-union startup competitor with a lower cost structure and more flexible work rules will come along and eat their lunch. Then all the union workers will get laid off anyway.
Unionization kind of worked for mines and factories because the company was tied to a physical plant that couldn't easily be moved. But software can move around the world in milliseconds.
Indeed, just look at the CGI VFX industry of Hollywood. US invented it and was the leader for a long time, but now it has been commodified, standardized and run into the ground, because union or not, you can't stop US studios form offshoring the digital asset work to another country where labor is 80% cheaper than California and quality is 80% there. So the US is left with making the SW tools that VFX artist use, as the cutting edge graphics & GPU knowhow is all clustered there.
Similarly, a lot of non-cutting edge SW jobs will also leave the US as tooling becomes more standardized, and other nations upskill themselves to deliver similar value at less cost in exchange for USD.
Unions _can_ protect against this, but they have to do it via lobbying the government for protectionism, tariffs, restricting non-union competition etc.