Fraid not! … Only one hit:
Option+w - nasal dot - ṅ ṁ …… ∑ ∑˜ ∑µ
Option+n - glide - ñ. …… ñ. 
Option+x - retroflex dot: ṭ ḷ ṇ …… ≈† ≈¬ ˜≈
Option+a - long vowel - ā ī ū …… aa î uu
Which operating system were you using?
I have iOS 15.6.1
Your original post is here
I just remembered, when all else fails, ask the Summer Institute of Linguistics (they do Bible translations into many languages).
I’ve just downloaded their Keyman for iPhone and iPad App. Will report back when I’ve worked out whether it can handle the bluetooth connectiion.