Having 18 games when it was 10-team league w/ double-round-robin, it's perfect. Expanding to 16-team conference, you can get more variety, but downside is fewer occasions each season playing home/away.
In traditional sense, 20 still seems like "a lot of conference games," but closer to matching reality than randomly dropping to 18.
I'd hope it doesn't mean we'd have 8 cupcakes, as your math accurately suggests. Either keep the two Big 12 games or replace those with two opponents at least close to similar quality.
This year was...
20 Big 12
1 Big East challenge (Marquette)
1 Iowa
3 Maui
6 cupcakes
Going from six cupcakes back up to eight would be disappointing.
If the problem is the Big 12 schedule is too condensed from January 1 to KC with 20 games then the solution isn't dropping to 18. It is playing some of them before break in December.
Plenty of time in November and December to play non-con games at a faster pace instead of once per week to give you some time for a one-game-this-week-not-two "bye" in early 2026. Play two quick after finals week but before Christmas to knock them out and then let the kids go home for the holiday.
Or maybe it won't matter and Purdue won't be the only one.
Converting two Big 12 games to cupcakes (even if the average Big 12 game now isn't as impressive as it was a few years ago) to Q3 or Q4 charity cases is a big dent in the strength of schedule. We've already had a reduction in Q1 opportunities in this new league -- this only makes it worse.