MacOS should come with a layout that's the same as the AltGr-international on linux - normal QWERTY, but AltGr(right alt) is used to type "international" letter

MacOS should come with a layout that's the same as the AltGr-international on linux - normal QWERTY, but AltGr(right alt) is used to type "international" letters, i.e. RAlt+y = ü, RAlt+q = ä, RAlt+p = ö, RAlt+s = ß and more (using RAlt+vowel gives you the accented variant).