I know that RPC stands for Remote Procedure Call. Does Bitcoin Core do RPCs with other nodes on the network?
No, Bitcoin Core speaks the Bitcoin P2P protocol with other nodes.
The RPC interface is specific to the Bitcoin Core software, and for communication with the (human) operator of the software (through the
bitcoin-cli tool), or for other (local) software to interact with (e.g. instructing it to create addresses, send funds, compute statistics, ...). The same commands can also be given in the Debug window in
You can find documentation about the various supported RPC calls on https://bitcoincore.org/en/doc/.