I've always wondered why Russia did not use its airforce to its advantage. In the first day of the invasion they had very few aircraft in the air, when on paper Russia should be able to field hundreds or thousands of aircraft.
It took a while to work out why and the answer is they can't. They overbuilt their logistics a long time ago. Back in WW2 there was a saying the US had in the pacific - what was the point of building lots of planes if you can't get them to the fight.
Russia may have a lot of aircraft on paper and even if I take that at its face value and assume the numbers are right and the aircraft are all operational, the reason Russia couldn't use them is they don't have the logistics for it.
I still find it a bit of a mystery - there are some factors though:
They only managed to destroy a partial amount of Ukraine's air-defences in the opening attacks.
Their training has revolved around either small scale counter-insurgency type stuff or all out war, they have relatively limited institutional knowledge and experience there to support large scale, complex multi-layered air operations supporting combined arms. While grossly simplified they have tended to utilise the air force along the lines of fly here, bomb this, return - they tend to have limited real time data on enemy movement (beyond AWACS, etc.) which limits flying more dynamic missions.
Actual combat operational aircraft is well below on paper numbers.
Probably concerns about how well they could maintain discipline - a large scale air operation is difficult to keep everyone on the same page and organised with a risk of pilots getting off-mission and say a bunch of them accidentally invading Polish air space and kicking off a big incident.
I don't think logistics is entirely a problem here - they've managed some reasonably sizeable bomber operations.
These kind of factors have apparently made the Russian airforce somewhat risk adverse, something Ukraine taking the air war to them might risk forcing them to confront, unless Ukraine has the capabilities and free hand to take that side of the war into Russia, it potentially works against them if Russia is forced to address their deficiencies.