In practice, I type those characters on their own much more often than I type them for French characters, so having to press more keys for the French ones makes more sense than the other way around.

There's also the fact that I have to type those characters in places where I don't have fancy entry systems (drive unlock passwords, rescue environments), while I don't type French in those places, so it also makes more sense for muscle memory.

Ah yeah, I generally just switch between US and US-Intl when I need to move to French. Since you can do it with Win+Space, it's pretty convenient, though I do sometimes trigger it on accident.

I don't use windows often enough to have gotten the hang of how it handles layout switching. I think, by default, it's supposed to handle them "per app". Which, in my case, sounds great: I need French for Outlook / Teams, and English everywhere else. Somehow I always seemed to type expecting the wrong layout. So I've looked for a way to have a single one which works everywhere.

Windows doesn't natively support the Mac behavior. I had to find some layout that almost does it, with the caveat that it uses alt-gr instead of mac's alt, which isn't exactly the same nor in the same spot. So I had to pile another utility on top that modifies the WIN/Menu keys to send alt-gr. Luckily, it was also able to move win to caps. So now, aside from the "weird" altgr, I'm happy enough with my keyboard under windows.