“Russians don’t have air superiority? They say it themselves by not flying missions...”
https://www.nytimes.com/2022/05/09/us/politics/russia-air-force-ukraine.html
May 9, 2022 — Russian warplanes are generally flying 200 to 300 sorties each day, a senior Defense Department official told reporters during a briefing
From your own source:
“Russian planes, pilots and air-to-ground weapons have all grossly underperformed in the war against Ukraine.
The absence underscored President Vladimir V. Putin’s failure to build a capable modern air force, as Russian aircrews race in and out of Ukrainian airspace and heave unguided bombs while fleeing enemy surface-to-air missiles that Moscow has still not managed to destroy, even after 75 days of combat.”