The last two places I worked at that had office 365, everyone just used the web interface. It was pretty miserable but beat having a separate application just for email.
There's an open source project to fix it though: https://alt-tab-macos.netlify.app/
Together with an app to fix the scroll wheel and a calendar widget, working with MacOS becomes almost bearable.
I don't go low on ram often enough to notice anything, or the exemption still works.