No cats, no carp.....cats aren't actually bottom eaters in the hierarchy of the foodchain, they are competing directly with Bass for forage. Carp on the other hand can out breed Bass which destroys a small pond's carrying capacity, and equally as bad feed on the lake's best Bass habitat, the aquatic grasses.
This is a rabbit hole if you really want to grow huge Bass which in your rare case, actually can due to the your climate. Bob Lusk the Pond Boss is beyond reproach, he is the man to learn from.
You need three things to grow big Bass
Water quality You need to check the PH and adjust if need be and then "fertilize" yearly for the plankton and zooplankton blooms that occur in the spring each year. The micro organisms are the building block of all life in your fishery.
Forage base....since you got your quality right, you can stock Threadfins which feed on the phytoplankton, along with your Bluegill.
Habitat.....Both Big Bass and their prey/offspring needs good habitat in order to thrive, this can be a mix of natural aquatic grasses native to your area, or manmade cover, wood laydowns you might create, fish caves, etc.
Let the forage base establish for a few months, then add F1/Tiger/Gorilla/Lonestar Bass fingerlings into the pond.
Don't stock anything but the above!
Lastly wait about 5-6yrs and start catching homemade DD Bass