Is this laptop permanently airgapped? I.e. it has never been online, nor will it ever go online. Even better if you didn't even put a WiFi or ethernet card in it so it physically can't go online. If not, permanently airgap it then format it and reinstall your distro of choice.

After that, the set up I would use would be to run Core on your main online computer and run an Electrum server on this computer as well. Then run Electrum on your airgapped laptop, set up a new wallet, and create a matching watch only wallet on your online computer (which syncs only via your own server). You use the online watch only Electrum wallet (which does not contain any private keys) to monitor your addresses and create unsigned transaction, and your airgapped Electrum wallet to sign those transactions (after transferring them back and forth using either a USB drive or a QR code).

You could also skip Electrum here and do the same process just using Core, but lots of people find Electrum easier to use. You can also use your Ledger device with this set up, and interact with your Ledger via Electrum on your online computer, again routing everything through your own Electrum server connected to your own node.