Can’t find correct replacement for Kohler shower/tub faucet.

Existing tub faucet and shower are Kohler. I always thought the different brands had their own unique valves, so stuck with Kohler. I bought and tried 2 different kohler units and none fit. Did Kohler change? What brand or model can i get so i dont have to replace the entire valve/plumbing unit?

Im not a plumber or handyman, but i do just about everything around the house myself, forgive me if i’m using any incorrect terminology.

This is what i had. Any help or direction is greatly appreciate.