This is a fantastic study, and I've added it to my list of links for how to learn about voting methods (https://voting-in-the-abstract.medium.com/how-to-learn-about-voting-methods-4e6c0e4d38d9). It's every bit as good as a similar study for the 2016 Presidential election (https://www.researchgate.net/publication/352547793_Comparing_voting_methods_2016_US_presidential_election), and the fact that it focuses on a hotly contested nonpartisan election makes (in my view) a better model of political culture that voting methods reforms hope to create (that is to say, it's not dominated by a two-party system). The fact that you use a non-representative sample election is arguably a downside, but at the same time, it's very interesting as a picture of how an election can go when voters have mistaken beliefs about which candidates are viable.
I found the look at how voting methods and money in politics interact especially interesting. I don't understand this interaction well at all, and to the best of my knowledge it has never been the subject of a rigorous evaluation. But this post makes me increasingly convinced that it's important. I've also found that campaign spending probably played a big role in the 2022 Australia elections under RCV (https://voting-in-the-abstract.medium.com/rcv-in-the-2022-australian-election-cdc9a8b77d84), but that just told me that it was (probably) quite important; it said nothing about whether Approval or STAR Voting could make it less important. What you've got here is the best evidence I've seen to date.
Again: great article, and I hope you'll conduct a similar study again the next time Chicago has a mayoral election.