Birds are funny creatures, nothing like dogs or cats who seem to usually favour the person who feeds them and spends the most time with them- birds don’t care who does all the hard work or who they’re supposed to like the most… they like who they like and that’s all there is to it really.
I have a rescue Sulfur Crested Cockatoo, I am the only one who feeds him, gives him fresh water, new chew toys, new perches, cleans his enclosure, let’s him out for out of cage time, I am also the only person who regularly talks, spends time with him and shows him attention… he still prefers my son and my cousin to me and he tries harder and harder every day to bite me- he nearly fell from above my head yesterday trying to hang down to bite me, I saved him from falling and getting hurt again and the thanks I got for that was an even bigger attempt to bite me lol.
You could try being the only person who gives your bird it’s favourite treats, you could try target training and other activities that open up and grow your communication abilities/level, but at the end of the day, they sometimes just choose who they choose as their favourite person for no obvious reason and we have to accept it- that is just the nature of keeping birds as far as I’m concerned.