The 30T granny has a 74 mm bolt circle and chainrings in this BCD are available from many sources down to 24T. Your two larger rings have a 130 mm bolt circle and 39T is the smallest commonly available and 38T the smallest that will fit.
Replace the 53 with a 50 or 48, the 30 with a 24 or 26, lower the front derailleur to match the new large ring and you should be good. A 12x48 high gear isn't that high.