On your https://polycub.com/staking page you'll see a PC/xPC ration this Ratio should keep going up. So when you exchange out 1xPolyCub it converts into 5.27 polycub tokens. You'll also see the USD value of that. It gets this from normal APR on the "kingdom" like with CubDeFi kingdoms and also 50% fee from those claiming earnings early in farms.

https://docs.polycub.com/resources/polygon-contracts here are all of your contract addresses for Polycub. You can either manually add in the PolyCub address or from PolyCub.com click on trade in the side menu and then exchange. It should auto populate it after a few seconds on Sushi.