Could you send a photo?
If your amazon sword leaves are more round in form, then that is the immersed form leaves those types will not survive underwater, they will eventually die.
immersed growth are when the leaves of plants are grown outside of water and the roots are underwater. They are not fully submersed underwater
It is best to just cut the leaves that are dying. When you trim the dying leaves you will trigger your amazon sword to produce new leaves. This also happens when you trim leaves that are not dying also, they will still produce more leaves.
Most of the time the amazon sword dying leaves will not recover, if they do it will take months for them to recover. It is more easier to just trim the dying leaf so that it produces a new healthy one in a couple days instead of waiting months for 1 leaf to recover. They are really fast growing.
Trimming dying leaves also help amazon swords not waste so much energy trying to save a leaf that may not survive.
That is good that you added root tabs, they will really help your amazon sword!