How many planes did the Essex-class have?
The Essex (at least in 92, which are the numbers from Conways) had 91 in 1942 - which when you think they pumped out 24 of them (and lost none in action), is massive. That's floating support for over 2000 aircraft, although a number weren't completed until after the war was over.
I'm not talking about 1940, i'm talking about 1940ies, as a decade. Also, Taiho is close to that. And one of proposed Shinano wariants had more than Midway.
Well, if we have 3 types of carriers- sure 30 is okay for CVL, not for CVE (I thought there were only two types of carriers).
And you said that - the smallest was 50. 50 is not 30. And after refit Lexington carried 78. Which is nowhere close to 30.
Yorktown, as 30ies-build carrier, had around 90.
Second Lexington, in 1942, had up to 110 planes.
You probably have to 'pick a spot' a bit more precise than the 1940s if you're looking to take an average - there's no way the average operational air wing capacity (as opposed to how many aircraft you could stuff in the CV, regardless if you could hold the fuel and ammo to operate them) of a 1940s CV would be over 100, but you may be able to pick a time when the Midways were launched/became commissioned, and get yourself an average over 100 then. It's a good deal lower if you include CVLs (which the game does), which didn't hit air wings of 50. The thing to remember that in-game, the "CV" is both a CV and CVL, so its base stats need to be more CVL than CV (or we get a lot of navies with CVs with larger-than-they-should-be air wings). If the game makes its base CV stat on CVs and not CVLs, we effectively get a HoI4 without CVLs at all - if, on the other hand, they make the base model 'CV' a CVL, with the option of using experience to build a full-fledged CV, you can probably get close enough for the devs vision to the range of ships that served, without needing an extra class of ship.
In terms of Taiho, while she could carry around 84 aircraft, she was (apparently, I'm going from Conways All the World's Fighting Ships, 1922-1946, I wasn't there) only able to effectively operate 53 (not dissimilar to the UK carriers, who could carry more aircraft than their aviation fuel load could support). As for the second Lexington carrying 110 aircraft, if that was after her 1950s refit, then it's out of our timeline, and if it was in the 1940s then the Lexington is on the top end of the scale for what the Essex class could manage, and not good as an indicative measure of the 'average' CV of the period.