Canada

I can certainly see proportional representation being more resistant [to authoritarian takeover?]. Certainly more than FPTP.

A country that is governed by its people, and truly so with proportional representation, is the strongest force there can be against an authoritarian takeover. It provides true and uncompromising democratic legitimacy to the government -- as a healthy democracy demands.

In 1998, the Supreme Court of Canada said:

A state whose government represents the whole of the people or peoples resident within its territory, on a basis of equality and without discrimination, and respects the principles of self-determination in its own internal arrangements, is entitled to the protection under international law of its territorial integrity.

Reference Question: Secession of Quebec [from Canada].

However I’ve grown up in a country with PR that’s pretty well captured by the owner class.

Hmm, I'd be interested to hear which country! However, I'm not going to give you a fairytale and tell you that proportional representation will solve all our problems -- it won't. But to have every vote count is a real good start.

Perhaps Canada is unique in that in spite of having a non-PR electoral system, we still defy expectations.