It's not rooted in "my guy good, your guy bad." It's rooted in "your guy is acting like an authoritarian, and here are the reasons why."
Some calling another "authoritarian" is their subjective opinion.

opinions are like assholes, right?
The same goes for his indictments. Those things all had to go through the normal process - grand jury, etc. - to get to the point they got to. There is evidence of crimes committed by trump, period. Purely political grievances don't get far in the courts.
Except NY State courts, apparently.
Have you forgotten the unique 'legal theories' on which that case was prosecuted?
Have you forgotten the unique approach of stacking lesser crimes to elevate the charge to a felony?
Have you forgotten that those unique 'legal theories' were not, and have not, been used on anyone else besides Trump?
Have you forgotten the meeting between the prosecution and the White House?
Have you forgotten the reassignment to a lesser position of prosecutor staffing from federal to state office specifically for this prosecution?
It was a pretty clear case of political targeting.
Seems like you've forgotten (ignoring) a great many things tainting this prosecution.
These things should tell you something, right there. But that it doesn't leads one to conclude that your partisan blinders are on and firmly in place.
"Firmly in control" is on the authoritarian spectrum. That's why we look at things he has done and compare them to previous presidents to make a determination.
A subjective look at what previous presidents have done and comparing them to a subjective look at what this president has done.
At least you appear admit that this is all subjective.
It's also legitimate to compare trump's actions and words to other authoritarians when making a determination. Vilifying minority groups? Check. Using the military for domestic problems? Check. Attacking the judiciary? Check. Defying the judiciary? Incomplete, but headed in the "check" direction. Fomenting hatred in general? Double check.
These supposed 'checks' you are listed are all based on what? The Dem's compliant and complicit MSM propagandist reporting and their smear campaigns?
The pro-Dem, pro-left political activism and political bias of the MSM already well established. I can provide citations to this effect if you dispute this.
OK. Gotcha.
So what? Generals make up a tiny percentage of the military.
Not at all a reasonable analogy. Do protestors follow orders as soldiers are expected to?
And preparing weapons doesn't bother you? Do you think that was a random act? Don't you think that, had things gone slightly differently, they might have retrieved those weapons and used them?
Having your weapons in the trunk of your car is legal, and is not the same as pulling them out and using them.
Your take on this goes beyond naivete. You are making excuses for criminal behavior, because it's your team storming the Capitol.
I have made no excuses for that behavior. Those that trespassed, vandalized, should be charged with trespassing and vandalism, and they were.
The SC questioning the use of a particular statute is their job. It didn't happen often under Biden; it's happening constantly under trump.
Not so much SCOTUS, but the lower federal courts a constant thwarting of what the electorate voted for.
Biden had his fair share of court battles as well, you may have forgotten them, but they did happen, most notably the Student Debt Transfer program of his, multiple court cases, culminating in the Biden admin just doing it anyway.
I hardly think that erecting a fence around the Capitol after it was violently stormed is "going off the deep end."
It was an over reaction to a one and done riot. Recall that there were a number of attacks on the Capitol over history, most often from leftist groups. Google is your friend, you can look them up.