You're correct. First, I find your analysis very well balanced. While I'm going to continue using Edge, you're "not wrong". I for one love my choices being criticized because that's how I've improved myself and my decision making through my life. I love informed people with a rational stance. Allow me to respond though with my reasons why I use it anyway.
My main reason for using it anyway is that I'm neck deep in Google's world, who I'm most worried about, and view perfect privacy as unattainable so I try to view most things as a larger effect overtaking a smaller effect. I need to get off my Google Account first, which applies to Maps, Youtube, Gmail and search. I use all of those. I view Google as having the most intimate view of who I am given they know where I go, watch, type, and look for. I'm making efforts. I'm moving to another email provider once I sort out how to transfer all my emails over. That'll go a long ways. That doesn't excuse privacy intrusions anywhere else, but Google is definitely my biggest issue. And the least trustworthy of all actors that I do business with.
For the browser itself, I balance privacy with other factors. I want a browser from a large vendor, capable of proper support over the longterm. Microsoft fits the bill there. Being my native browser doesn't hurt at all, it was Mozilla's development articles that opened my eyes to all the advantage that native browsers have over 3rd party. I also want performance if Firefox doesn't suit my uses any longer, the move to Chromium solved that. I agree with your assessment, I think it may be the best browser out now, discounting privacy.
I do keep Tor installed for any sensitive searches, which I do none of, but I keep it on my machine and phone (Onion Browser on iOS) just to remind me of how insecure most browsing is. Tor would be a good idea even for Firefox users. I do agree with the idea that the best privacy by default is a good idea, it's just not enough of a concern to overrule where Firefox and Edge are respectively today.
And lastly, I think there's room for improvement for everyone. I hope Edge continues to get better on the privacy front. I don't think any of them are cemented in their position, especially Edge as it feels unfinished in many ways on basic levels still.