Air forces played huge role in WW2. Fighters were important for establishing air control and that determined outcomes. There have been few examples since. The 1967 war between Israel & the Syrian-Egyptian alliance and follow up in 1973 were influential conflicts between modern (at the time) air forces.
In 1967, Israel won the air-war early. This basically won the war and fighters played a primary role. In 1973, Egypt successfully established a forward front using ground forces. Their missile air-defence made this possible, missiles made fighters ineffective in a limited area. If modern missile defence can do this for a 100x larger area, fighters might be confined to a much smaller role.
That was 45 years ago. Who knows where we are now, what's redundant and what's crucial. When WW2 broke out, there was a long process of figuring out what worked in a modern war. It's hard to know in advance. Big gun ships were thought to be very important, but aircraft carriers and smaller battle ships ended up being more important.
The US, Russia etc haven't fought a modern enemy in 2 generations. That's like building factories for 40 years which may one day need to produce goods. There's a high likelihood you are building the wrong thing entirely.