Formula transition at 12 months

My LO nxt wk will turn one. Still now she is on elecare infant for her intolerance of normal milk formula. Now im thinking give her normal milk formula just for a try to see if she can tolerate now. It was easy for us give elecare before but now she doesn’t want to drink this bitter taste formula anymore. So thinking to switch or give a try. Any advice or recommendations r most welcome mommies. As she is not eating enough formula she isnt gaining weight much ( born 7 lbs 3 oz and now 18 lbs ). Anyone on the same boat like me😔