For your future reference, I'm Brazilian and have always used US keyboards.
Every OS and DE I've used has the option to configure a US keymap with "dead keys", which works similarly to a typewriter - you type, for instance the acute accent (') and the cursor doesn't move until you type the next key, so if you do 'a it gives you á, 'c gives you ç, ~o gives you õ etc.
On macOS, I personally use the Brazilian - Pro mapping but there might be others. There's nothing particularly "Brazilian" about that mapping either so it might just work for you regardless.
I recall using one called "US International" or something similar on Windows and Linux.