I don’t even know that it was so much that the Axis AI was buffed rather than that the AI has no idea how to conduct Naval warfare at the moment, even with overwhelming force.
Barring US landings, the Axis should be able to seize Eurasia and Africa pretty easily, especially if Nationalist Spain wins and eventually joins Axis (Nationalist Spain winning is historical, them joining Axis is not, but happens most HoI4 games). It’s enough completely fresh troops, and they completely marginalize Portugal should it decide to ever join the Allies. They also take Gibraltar right away, which makes moving Allied ships through the Mediterranean quite difficult.
The way the game is currently designed, the USSR is basically holding out hope for the US to re-open the Western Front, and the AI is simply not doing naval landings against any kind of opposition with any success. In earlier versions of the game, you could count on it. Since MtG, good luck, you’re either gonna need to wait for a new patch or solo Axis as the USSR. If RNG goes against you and Japan wardecs you early you would basically need to cheese game mechanics to win. Either way it’s much more difficult than it was pre-MtG.