Hi and Welcome To TB. Please take a moment to check out the Stickies at the top of Behavior section Here on TB. Part of your problem is Simply maturation
at a very rapid pace for your budgies. This can be very frustrating for a budgies human family. Above suggestions are great to give your budgies time to grow. Provide supervised joint out of cage time then later reintroduce them with the less aggressive one going into the new home cage first. This will shake up the pecking order. Be sure to have 2 of everything:food dish,swing, toys etc. Best wishes as you watch your babies grow up.