I've always thought of Yharnam as more of a standalone city-state than as the capital of a larger country. A lonely, isolationist metropolis sequestered away in the mountains, having forgotten the position it once held as the capital of Pthumeru.

If it's to currently be the capital of a country though... I dunno. Yharnam has weird naming conventions and I'm bad at naming things. I'm fine with whatever y'all come up with.