X Is Wrong About Y
I have been finding it useful to say “X person in my life is wrong about Y issue”. Literally speak the words.
Without speaking (or believing) those words I spend too much cognitive capacity questioning my own beliefs. By giving everyone the benefit of the doubt, I create too much doubt in myself.
People are allowed to be wrong about issues. Saying so is not a condemnation of their person.
And I am allowed to be right sometimes. Saying so is not antithetical to being open-minded.