I'm not sure what kind of crank the thread starter has, but Wolf Tooth makes 36t and 34t rings that they say are compatible with 110 BCD 5 arm cranksets:
https://www.wolftoothcomponents.com/...oss-chainrings

EDIT: I see that SRAM Rival 1x crank specs list 38t as the smallest chainring. (And this crank is 110 BCD 5 arm)
I don't know if that is because the smaller rings from Wolf don't actually fit, or if SRAM just doesn't make a 5 bolt 110 BCD ring smaller than 38t. https://www.sram.com/en/sram/models/fc-riv-1-a1