Oklahoma won/tied the conference 5 times (2015-2019)
TCU won/tied Big 12 twice (2014* and 2022)
Baylor tied twice (2014 with TCU and 2019 with Oklahoma)
ISU won it once (2020) and OKSU won it once (2021)

Clearly OU is the top dog as they are a blue blood but unlike Texas often played up to potential. However with both teams leaving we are set to see a new hierarchy. Among the teams remaining TCU and Baylor seem to be the strongest remaining as both have played in NY6 bowls under multiple coaches (Baylor has had issues retaining a HC as one was fired and one went to the NFL). ISU and OKSU generally have finished in the top half of the league but it feels like their success is tied to their current HCs, Matt Campbell and Mike Gundy who have been at their programs for 5+ years.

I think BYU can hope to be as good as Baylor and TCU and can definitely be as good as ISU and OKSU if we have Kalani long term and he can generally have successful coordinators.