It’s a lot easier to come up with a balanced schedule if you have 6 divisions of 5 teams each.
20 series against your own division
5 series against the opposite league, own division
20 series against the rest of your own league
That leaves 6 series.
You could do another series against your own division plus two in the opposite league, or else all 6 series in the opposite league.
The own division, opposite league play would be nicely nested during divisional play, thereby minimizing travel expenses. The odd team out in each division would play each other.
Well, if you think there should be 32 “major league” teams (my personal choice would be 16), how about four eight-team leagues, five game round-robin (A v B, C v D, A v C, B v D), top 2 play World Series?