Turbo tax has added zeros to my W2 amount. I’ve redone that part to no avail. Says I owe almost half a million to the IRS! Can someone please help me with this??

You still have a typo, or it is coming from another income entry.  Delete the w-2 and re-enter it.   Preview Form 1040 and see where the typo is.   On what line is the income/tax showing?