I use the french azerty layout (fr-pc) on macOS (equivalent fr-latin9 on linux). It is an ISO keyboard, I am able to do all of the examples you wrote, and more: option b is ß, ã is option ~ and a, "é" is its own key, so is "à" or "ç".
I am able to write 120 words per minute, not so special, but good enough for me. I find the ansi/qwerty too slow with its compose system (I tried on the canadian-intl layout made for Québec).
I am able to write 120 words per minute, not so special, but good enough for me. I find the ansi/qwerty too slow with its compose system (I tried on the canadian-intl layout made for Québec).