Trezor with a semi-gapped laptop. Connect the PC to synchronize your wallet, disconnect, sign the transaction, copy the transaction somehow (ie: QR codes), veri

Trezor with a semi-gapped laptop. Connect the PC to synchronize your wallet, disconnect, sign the transaction, copy the transaction somehow (ie: QR codes), verify your transaction inputs/outputs, broadcast transaction. You can also go fully air-gapped by manually synchronizing instead of connecting to the internet. Edit: Alternatively, you could upload transactions via images (airgapped laptops) and sign them with your trezor (on the airgapped laptop). That should give the most security.