Not really an answer to your question, but many would argue that the term “authoritarian” in its modern connotation is practically useless. What I mean is that there is no single definition of the term which is specific enough to be applied and understood in the context of a specific country, political system, etc. While certain academic disciplines attempt to agree on specific definitions, the reality is that most colloquial usage of the term is solely to demonize nations or ideologies without meaningful critique. Here’s one of many articles on the subject, which I think gives a decent overview: https://www.peoplesline.org/p/authoritarian-is-an-analytically
What I think you are getting at with your question is that even in the way it is colloquially applied (“evil regime” / repression / lack of rights), the term authoritarianism is applied unequally. Actions that would be described as evil or authoritarian in somewhere like China are brushed off or ignored when they apply to so-called Western liberal democracies like the UK. To that I would absolutely agree, and I think that observation further speaks to the uselessness of the term in constructive dialogue.