Well, most of the fighting against "invasive mass surveillance and questionable social engineering practices" has also been done by leftists, so there's that...

Centrist average Joes usually don't care about such things, and right wingers applaud them to help the police and such.

As for libertarians they are against them when it's by the government, but fine with them when a private company (even one the size of a small nation) does it as part of a "voluntary" employment contract.

True. There’s the hippie leftist archetype, and the commissar leftist archetype. It’s a spectrum, so they say!

To me spectrum implies a single dimension, i.e. the spectrum of light is just based on wavelength. But this metaphor doesn't really fit with politics, which at best can be reduced to two dimensions (in my opinion), and realistically is a lot more.

Realistically the left/right spectrum is orthogonal to the authoritarian/libertarian spectrum. Classic liberalism is, I think, more aligned with the right but also profoundly anti-authoritarian. Similarly, the left has a proud tradition of supporting individual liberty but also a strong tradition of suppressing it in favour of collective power.

Corporations of all stripes tend towards authoritarianism though, in my view. It is a natural structure when you have agents using someone else's capital.

No. The claim is that all corporations tend toward authoritarianism. Left and middle and right. Not at all horseshoe theory.

You are conflating leftism with authorarisam