First thing is you need to gain its trust. It needs to know you are the one feeding it.
for the first month I had my bbxb I fed it meal worms, Dubai roaches, shrimp, and red worms. All really treat type foods to establish that I was the food source. Mine was already eating shrimp regularly so I had that going for me.
I put the pellets that I want to feed the aro in as food for meal worms and super worms. To get the ball rolling in that direction. I would also soak pellets in shrimp juice and feed the pellets first. After about a month of the aros trust being built up I would stop feeding all the really nice things and only offer pellets. It was a slow go at first, and it looked absolutely pissed at me, but I didn’t give up.
now it eats pellets 90% of the time and those other items are more for treats than regular diet.
each fish is different, but don’t give up or give in and you can get it eating pellets.
oh and everyone is going to tell you that you need a bigger tank and filtration etc. ????