With hardware wallets like Ledger you don't have access to your private keys and they never leave the safe environment of your device.
You have your seed words. Even if you connect your Ledger to Electrum you still can't see your private keys. You don't need them if you are using a Ledger HW. Just make sure your seed is kept away from prying eyes and never store or enter it anywhere online.

One private key unlocks access to one address. You can have X number of addresses. The seed unlocks access to every single address generated in your Ledger Live.