Yeah, Carson has flip flopped now and again. No doubt. Still not nearly as much as Trump has. Heck Trump was a Democrat for 8 of 10 years between 2000-2010. Trump has “evolved” on so many issues it is impossible to keep track of - INCLUDING immigration. In 2012 “the Donald” said Romney was too tough on the issue of illegal immigration for simply wanting to enforce eVerify. Even as of a few months ago Trump thinks socialized medicine works great in Canada and just terrific in Scotland.
If you want a real conservative, one grounded in conservative ideology - then Ted Cruz is the guy. As a politician he’s no doubt changed his position here and there, but for the most part you can count on Cruz to be a conservative on nearly every issue. With Cruz as president you will never have to worry about liberal administrative appointments, liberal nominees, liberal regulatory schemes, etc.