This behavior varies even between different applications within macOS. Apple Pages seems to delete / select / cursor by Vowel+Consonant cluster. TextEdit seems to delete by code point, but cursor / select is by Vowel + Consonant cluster. In general, the TextEdit behavior seems favorable.

Gurmukhi has only three commonly used half/subjoined consonants for ਹ ਵ and ਰ. Most Gurmukhi readers are not familiar with the concept of Halant / Virama and thus deleting behavior should delete the full half-character.