Where can I find my Bitcoin core key? I bought some bitcoins a few years ago using Bitcoin Core.

I have since discarded my computer as it broke.

Where/how can I find my bitcoins?
If you recover your wallet.dat file, you can import it into a working bitcoin node and sweep the wallet. You must have access to the hard drive of the broken computer.

Your wallet.dat file can be located at:
Linux ~/.bitcoin/
Mac ~/Library/Application Support/Bitcoin/
Windows%APPDATA%\Bitcoin

You can also import the .dat file into blockchain.com which naturally I do not recommend since it defeats the purpose of decentralization.