I'm skeptical about complex voting systems, simply because they cause a lot of confusion and some people don't understand what they're voting for.
Here in Germany we get two votes for the Bundestag, it's essentially a split between district vote and federal vote. The system is pretty simple, you get two columns, one with people, one with parties. And many voters still don't understand the implications of it.
My city's council has such a stupid voting system (multiple votes, multiple districts and parties), that it took me and my friends (all having masters degrees or doctorates, one literally being a pol sci teacher) several hours and an absurd chain of local/state websites to finally find a Word(!!) document that somewhat explained the process, and we still don't really know what was happening.
My point is not that 80% of people are too stupid to understand these systems, but too lazy to look for information, and that's fine. Even the stupidest voter should be able to find and understand the system within 5min. If not, information is obscured or the system too complex.
Either you fell into establishment propaganda or peddler of it. Any system will develop extremists no matter what, if the establishment are too corrupt, and people are pushed to look for alternatives. Canadian PM Trudeau scrapped his first-term election promise of ranked choice voting after "looking into Europe" and said the same thing as you; and yet the Canadians have developed their own far-right lunatics over the years. And US has the Republican Party morphing already into another fascist party, all without copying any sort of multiple choice voting system from others or developing their own.
All the people arguing for RCV are hoping it will solve their problems. I’m skeptical.
There are loads of other voting systems in action out there. Some of them guarantee full proportional representation to their respective countries. Generally what we see in those countries is a ton of different small, special interest parties with a few seats apiece. Then you end up with these bizarre coalitions where a bunch of unrelated special interests band together to form a government which roughly half the population ends up hating anyway. Israel is a prime example of that.