What does authoritarianism mean in the Syrian context?

Syria won its independence from the Ottoman Empire, and then again from the French. They abandoned the monarchy that was put in place there, and Gulf State monarchies, with American assistance, have been trying to get footholds in the country with their proxies. These proxies are heavily fundamentalist, theocratic, and unfriendly to minorities, so it's not surprising when they have a continuity with groups like Daesh.

"Suppresses dissent" is not a good definition, we see that in most countries. "Conducts mass surveillance of citizens" is not a good definition, we see that in almost all countries. "Dynastic" is also a poor definition for the same reasons, as is "sham elections/democracy".

What we have is a remnant of the pan-Arab nationalist, social-democratic pole of the broader Arab conflict in the Cold War. It's been revised and watered down, and it picks up a lot of neoliberal policies, but it remains the best guarantor of a pluralistic and independent society in Syrian nationwide politics (not counting the regional entity that is in a permanent truce with the federal government).

"It's impossible to know one way or the other" is a weak stance. Recognize the dynamics of power in war and media, and decide which story you think is more compelling: the one that lines right up with the CIA and State Department, or some alternative to that.