Have you tried altgr-intl layout? us-altgr-intl is a variety that exposes accented characters through AltGr-combinations. I have to type in Scandinavian, Germanic, French and Latin languages and they're all covered. As a bonus it's consistent between platforms, included by default on all distros I know of, and except the Altgr-combinations it's just like the vanilla layout.

If you're on X11 you can try out the en-us variant by

  setxkbmap -layout "us" -variant altgr-intl

You will inevitably need dedicated keys (e.g. use the numbers row for this, keypad for numbers) for accented characters if you use type in an accented language actively.

For cases when you just want an accent occasionally compose key is great.

The Mac way (long-press, select) looks cool but it hardly is convenient to press and wait seconds for every accent if it's there in almost every word.

This exists on linux (PopOS). I think it’s called compose key under GNOME settings.

not true, had this for decade, never grew on me bc it's just unintuitive. US International keymap on demand on Windows is far superior

Same, I was hoping this did that but judging by your comment I guess it doesn't