[1] I've daily driven it back in high-school, for all that's worth. Wrote assignments in troff and all. Some people might be able to tell of less mundane success stories as well.
The scroll wheel on any wheelmouse is a button and you can click it as well as spinning it.
All wheel mice are also 3-button mice.
https://github.com/artginzburg/MiddleClick-Sonoma
Works well, but I miss the physical middle button on my Thinkpads.
The chording isn't really cumbersome, just unfamiliar. You get used to it quite quickly with a few tens of minutes of practice.
The Macintosh Toolbox is a bit verbose, though.
Note that because it's an API-compatible reimplementation of AmigaOS, it's not really a "fantasy OS". Hosted mode is rather a tool for serious OS development. Nevertheless, it's much more like a modernized retro Amiga than it is any extant DE for Windows/Linux/Mac.