I would say to get some lower acid coffees that still have rich flavors, you should try some of the Indonesian coffees - Sumatra, Sulawesi, and Java. To my palate, if they are roasted to more medium than lighter, they get a deeper and earthier flavor as well that is much different than the bright acidity that you don't care for as much.
I don't make lattes or caps at home, but I would think they should work decently as a single origin espresso, or another option would be to keep an espresso blend on have for when you make those? For that I'd try to find somwhere local or you can get an espresso blend from pretty much any roaster that I have posted pics of too.
Hope that makes sense and helps!