whats the best way to farm vangaurd engrams. played hella nightfalls on legend not getting any

[wicked oxide]

dss

[gentle urchin]

gms and when bonus rep for vanguard is on

[eternal pumice]

the only way to get vanguard engrams is when you get rank up, with 16 being the max before prestige.

the farther along you are in reputation the further between ranks and more time it takes to get an engram