Suppose you have the classic 2 laptop setup where one acts as an online node to create the raw unsigned transaction (now I think this can be done easily with the PSBT file) and then the other laptop as the airgapped Core instance where you load the PSBT file and sign it, to then send it back to the online one to broadcast.
Anyway, my question is: How does your airgapped Core instance look like? Do you just leave it trying to sync forever? Is it possible to stop it from trying to sync?
Perhaps some work could be done in this direction? to have an "airgap mode" where you just load Bitcoin Core as a storage box of private addresses to sign PSBTs and control the funds with watch only addresses in the online laptop? I think this is the idea of "Armory" but I only trust the Core software at this point because it's the most peer reviewed one so I would like a Core solution for this one. As far as PSBT tutorials I only see them aimed for hardware wallets but not for airgapped computers which imo is a more powerful tool. I will have to try in testnet exactly how it works. I assume when creating a PSBT file on the GUI you are asked to manually enter where the change will go so you enter an address there that you own on your offline wallet to get the change.
Anyway I would like to know someone here uses this 2-Core airgapped setup and how do you do it.