May I weigh in on the Dutch/Belgian view of a high-low mix where F-35 is high and M-346 is low? Two decades ago USAF said F-35 was part of a hi-low mix, with F-22 high and F-35 low. And two or more decades before that USAF said F-16 was part of a high-low mix with F-15 high and F-16 low. Holland and Belgium bought F-16.
It seems to me that the hi-low mix has been bantered about for around half a century now and is nothing new. But high-low is relative. One force's low is another force's high. And one force's trainer is another force's low end fighter (Hawk? F-5 Tiger? A-37?, etc). And with the M-346 being offered to fill USAF's T-X requirement and likely their "red aggressor" requirement, the M-346 could become a very capable (and maybe cheap) weapon platform and effective for conflicts other than near-peer. Or would used and refurbed A-10s be even better and cheaper?