I need a flutter engineer

this is the app now, I need a 5v5 maker so there are certain players already listed on there stored on a database. I need the coach to be able to select 10 players and it will divide the 10 players into 2 teams based on rating, that the coach has already given them. Most of this is already in the program as you can see, but I need to be able to organise into 2 random teams each time with close to similar average rating. I just need you to develop one screen that looks like the screenshot uploaded.