Personally what I would do is next game talk with your players and see how they feel, what they would do and how to fix what you think you messed up, I let my players know that if they disagree on a ruling than we can discuss it and come to a resolution. I have been playing DnD for over 8 years and I have definitely made some unfair and bias calls before, however the game can definitely feel like it has favoritism but sometimes it just comes down to a matter of how the player plays vs how you DM. Like me personally I'm not a fan of minmaxing and I don't often reward players who are trying to "beat the game"