What's the recommended way to run an offline airgapped signer in a general purpose PC?

I see that Specter supports Electrum as a signer. Is that the best option for using an offline signer in a general purpose PC?
The FAQ says that full support is not there yet. What is currently missing? is it only that transactions can't be passed via QR codes "natively" in Specter, which means the user must either use files (which breaks the airgap) or use separate software to pass the transaction via multiple QR codes?

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