The Ukrainian AF tweet also states what it needs to counter Russian aviation. Look at it as a shopping list instead of a admission of defeat. They want to get their hands on 4th generation aircraft, F-16s, F-15s, more and better surface to air missiles, S-300s and 400s, Patriots, NASAMS.
They are getting more weapons now, more Stingers, British Starstreaks (extremely good), and current anti-tank rockets and missiles. They need heavier weapons to carry the fight. Those weapons, Tanks, heavier SAMS, and fighters, take more time for governments to approve and deploy than man portable weapons.
The Russian air force has shown it is having the same problems as their ground forces. They are mostly using daytime operations, no coordination with ground forces, and limited use of guided weapons. That is fine for bombing cities block by block. It is not good enough when the enemy has comparable weapons to fight back. Russian aircraft are not going into areas covered by Ukrainian's medium and long range air defense missiles.
Ukraine is the size of Texas. Russia has shown poor ground control and airborne early warning needed to counter the Ukrainian AF. If Ukraine was going up against USAF AWACS, F-15s and F-16s, they would have been out of action in hours.
On the first day of the invasion Russia only fired a few cruise missiles at airfields, did not put one out of action, and called it a day. No matter their size or what they claim they are capable, how they are fighting is their actual level of competency and effectiveness.
It’s outright fantasy to suggest that Russia is losing to the Ukraine’s garage sale/potluck efforts to arm untrained citizens and train their pilots on gifted next generation jets. You are quoting MSM liars and traitors like they are gospel, despite the realities of modern warfare.