@Primeoz56
Game.creeps.creepname can work, but only if your creep is literally named 'creepname'.
however if creepname is a string containing your creeps name you need to use this syntax instead.
let creepname = 'george';Game.creeps[creepname].move(TOP);
Note. you can go much farther with this syntax and replace all but the original object.
Game['spawns']['spawn1'].createCreep([MOVE],'george');