Re: Easy fix
"because they will be firing missiles."
Bear in mind that a dogfight is considered to be any air-air engagement carried out at short range with the aircraft maneovering around one another to try and establish a firing solution against your opponent, or avoid the opponent establishing one against you. Some people might therefore choose to believe that this implies dogfights and missiles are mutually exclusive, but those people would be wrong - once you're close enough such that you can no longer simply point your nose roughly in the direction of the target, pull the trigger and wait for your missile to do its job, then you will want to have at least *some* basic menu of maneouvres available to you so that you can still get into the right position to make use of those shorter range missiles and continue to avoid having it degenerate into a "whites of their eyes" gunfight.
And even with the advent of more capable short range missiles offering off-boresight targetting, such that you may no longer need to maneouvre into a position where the target is somewhere in front of you, even these missile systems have their limitations, and there will always therefore still be scenarios where, no matter how capable your missiles are, being untrained in the art of dogfighting will put you at a disadvantage. Which is the polite way of saying your life is now in the hands of your enemy being even less competent than you...
So yes, if you feel supremely confident that,
your BVR missile systems are capable enough to kill targets regardless of a) how well trained their pilots are in evasive maneouvering and b) how effective their ECM systems might be, AND you're also confident that every air-air engagement will occur within scenarios where use of such missiles is permitted and possible,
OR if you're then at least supremely confident that, should killing them with BVR missiles be a non-starter for any reason, your shorter range missile systems will then still be sufficiently capable such that you STILL don't need to bother with any of that maneouvering dogfighty nonsense,
THEN you might, possibly, start to consider that continued investment in dogfight training and weaponry is a complete waste of time and money.
That's a far easier consideration to be making if you're doing so from the comfort of an armchair as opposed to an ejection seat - I rather suspect that if YOUR life was on the line here, and you were being thrown into a combat scenario where you risked death because someone else had glibly dismissed the need to give you a fully rounded training programme, you might be somewhat more conservative in your expectations re how well the stuff you had been trained on might actually perform in a real world encounter against an enemy whos capablities your own side can only estimate, and who isn't going to want to make it an easy win for you.
"so why would there ever be dogfights"
Because the Ukranian Air Force isn't the only one on the planet who may, at some point, end up going up against Russia or an equivalently-equipped adversary. And at least some of the others who may end up having to do it in the future DO have rather better SEAD capabilities either natively or collectively via whatever alliance they'd be operating in at the time, which means their ability to make more use of their own aircraft in the offensive rather than defensive roles is in turn rather better. And as soon as you make it more likely that air-air encounters will take place, it's only a matter of time before you have an encounter where it's something other than a BVR-missile-based turkey shoot with your pilots all making it back home in time for tea having barely broken into a sweat.