Sometimes they are. Especially for Bluetooth. Check the layout of your phone SoC.
Ouch... ='( Well... Do a warm wallet using the Android and meanwhile source/build the seedsigner.
Why not get a hardware wallet? It's pretty much exactly what you want.
Hmmm... Any hardware wallet that is fully air-gapped, can do multisig and works based in QR codes to recommend mate?
Quick search suggests Trezor. I've never used a hardware wallet. If I needed one, I'd make one myself.
Yeah... I will most likely invest the time and money to build a seedsigner. Good thing that AirGap Vault works for my immediate needs. Thanks in any case man! =)
Welcome. You are likely greatly overestimating your threat level. Hardened Android in airplane mode is totally fine. $300 you put into building and configuring your own wallet is well worth it in terms of gained skill. The scene needs more physical projects like that instead of another bullshit service for speculation