Prestige gets you $4/miles plus bonus base on years of relationship with Citi, which should be the best no cap card.
Alternative is Dahsing BA card, depending if you like AVIOS, $4/avios, no cap as well.
Shouldn't be a problem for 1-2 million /year, at least, for Prestige and BA card.
For JPY spending, definitely Fubon, (Cap at 20k per month, 2 months max in a year, registration needed) for 1.5/miles.
$4/miles should be good enough to cover the 1.95% forex fee.