Decent analysis, but it has one major problem.
He raised a good question, which we already discussed on this thread: Why didn't the Ukrainian Air Force interdict the huge logistics convoy which the entire planet watched slowly rolling towards Kiev? The obvious answer is that Russia indeed has Air Superiority.
The problem though is the manner in which he describes Russia achieving air superiority. His claim is that Russia is relying mostly on its S-400s/IADS. Thats a big assumption. He cites only 1 kill that the S-400 got at long range. Moreover, the problem is in the concept, because relying mainly on your SAMS would create deconfliction issues in the airspace you're trying to dominate. I suspect the CMs and Air Strikes on Ukraine's airbases had more of an effect than the S-400s. We even saw one of the Ukrainian airbases completely destroyed by a FOAB, which was dropped by a strategic bomber.
The fact that Ukraine was desperately requesting Polish Mig-29s indicates that the S-400 are not their main concern. If they were, then it would be pointless to ask for more Migs. The request for more Migs indicates that they've actually lost most of their air force. It was either disabled on the ground, or it was splashed in combat (or both.) But more data is needed here.
Another issue which he didn't address, and it hasn't been discussed much on this thread either, is the weather's effect on Russia's air campaign. After the first few days Ukraine was covered by clouds. US intelligence correctly predicted that this would cause problems for Russia's CAS efforts. The next day, we got all the footage of MANPAD kills of Russian fighters and gunships. This slowed Russia's air operations for a time. So weather played a big role in the attrition here.