Improving User Preference Tracking for Consistent Data in Mixpanel

Hi, is there any better way to get a consistent number regarding how many of my users have permanently selected one choice over another? I've tried multiple solutions and each of them provide me a wildly different answer. Ideally, I should be able to answer a question like "Out of all of our users that use the app every day, how many of them prefer X over Z theme?" It isn't in our best interest to track every single theme change as a user property, because that would create chaos in the data over time, and bloat the app. I wish I could simultaneously use the 'last segment' breakdown and use a custom denominator, or a cohort where there was an option to select 'choose the most recent value'. Any thoughts? I've been struggling with this for at least a year in Mixpanel, and no solution is really good enough 😕