Microsoft would be the one forking Chromium in this case, so I really don't think that's true. Microsoft is more than capable of doing it.
A features-based approach seems iffy. They can't push speed or site compatibility anymore, assuming MS doesn't completely mishandle the build. Even tiny Vivaldi seems to remain coupled closely enough to Chromium releases that it will be hard to say "theirs is so out of date and missing the latest and greatest."
If they try to deliberately hobble ChromiumEdge, it seems like it wouldn't look good to regulators. "We didn't test Gapps on Gecko, oops, it breaks" is one thing, but it's hard to keep a straight face saying "it mysteriously works in our version of Chromium and not Microsoft's"
Many of the differences they'd likely differentiate on (the sticky Google login, telemetry) are not features for the consumer, they're the features that benefit Google and justify the cost of developing a browser.
Which clearly didn't mean anything [1] for increasing market share.
[1] https://ferdychristant.com/the-state-of-web-browsers-f5a83a4...
In the web's short history we've already seen several browsers rise and fall. It's possible Microsoft may in the future repeat what Google achieved with Chrome if it can find a new edge to compete, pun intended.