Keep the first day classic, then use the second for a different rhythm or a nearby landscape.
Day one: Bled itself
Use the one day structure, but slow it down. Walk, choose one classic sight and leave the evening open.
Day two: choose contrast
Pick Bohinj for another lake with more national park character, Pokljuka for forest and mountain access, or Kranjska Gora for easy dramatic scenery.
If you prefer not to drive
Stay closer to Bled and use Vintgar, Radovljica or a bookable activity with transport where available.
See bookable experiences around BledAffiliate booking link. You pay the same price.