That's why, when I need to be clear about it, I say spicy hot (because hot in itself is also rather ambiguous) and uses a lot of spices when describing something that is rather more flavorful.

English is just not very good at describing flavor. Looking at British food, there might never have been the necessity.

In German there's scharf (spicy) and pikant (slightly spicy). As well as würzig (spiced).