Growing up I barely ever heard anyone in the family use the term "sanAtana Dharma"
I came across the term in Manu Smrti where it used in a different sense
सत्यं ब्रूयात् प्रियं ब्रूयान्न ब्रूयात् सत्यमप्रियम् ।
प्रियं च नानृतं ब्रूयादेष धर्मः सनातनः॥ १३८ ॥
Less so in the South
I suspect the Arya Samaj had a big role to play in popularizing this term
Hinduism is OK
Alternatively -
vaIdIka Dharma
Brahmanism
Though the latter two pertain more to the religious practices of the elites