aaah yes youāre right!! I totally see it!!!
Dia would totally be in denial, I mean after all, how can she fall in love with someone who couldnātĀ even pronounce Muse correctly? But then she gets to know Chika more and realizes that she loves Muse and idols just as much. And of course she wouldnāt know as much about Muse, she only recently got into them! And with that acceptance of Chika, she slowly comes to see Chika as the cheerful and shining person that she is, who is passionately chasing after her dreams. And along with feelings of gratitude that she definitely holds for Chika for bringing her back into school idols and letting her join Aqours, she realizes....aah oh no is this love???
And of course, Chika is oblivious to it all XD