be not fussed (about someone or something)

To not have strong feelings, either positive or negative, about someone or something. A: "Do you still want to try and go to the match tomorrow?" B: "I'm not fussed, to be honest. It would be nice to spend the day with you." A: "Would you like beef or chicken for dinner?" B: "You decide. I'm not fussed about either one."

not be ˈfussed (about somebody/something)

(British English, informal) not mind about something; not have feelings about something: It’d be good to go there, but I’m not that fussed.