Get a USB key and install TailsOS with persistance.
Plug the USB on an airgapped computer (that computer will never touch internet again) and create a wallet with Electrum. Write the seeds somewhere.
Take a picture of your public key QR code from Electrum and create a watch only wallet from a hot-computer to watch your savings grow.
When you want to move BTCs, create transactions from the hot computer (watch-only), and sign them using the cold computer + USB key. Broadcast the Tx from the hot computer. Move data from one computer to the other using only QR codes.
You can have multiple flash drives just for fun of having multiple backups. All flash drives have storage that are LUKS encrypted. Make sure you use a strong passphrase.