Re: 2.5MW
"If stealth was totally useless why are all major nations persuing it?"
The question isn't why they're pursuing it, it's how much they're spending in doing so (not much) and what level of committment they're giving to it vs other forms of aircraft (not much, it's just experimental)
Superiority might have been a SF story, but in large part it was based on Nazi vs USA approaches to WW2.
The difference these days is that the overcomplex tinker toys belong to the USA and whilst other countries are playing around with stealthy shapes they haven't committed virtually their entire aviation R&D budget and purchase committments to such aircraft nor are they hiding vast amounts of GDP overspend into military budgets at cost of investment in education, basic infrastructure and public health.