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I think that the main vulnerable node is not PC, doesn't matter if its air gapped or not. The seed phrase is the main thing which needs to be secure. Without it there are no possibilities to look into the wallet, regardless of the presence of other software tools... So, I think, its not necessary to protect acounts via air gapping, since the seed phrase is anyway a deal.
Aside from what @satscraper already said, people usually don't have to worry whether their seed/recovery is secure or not. Any decent Bitcoin wallet generate seed/recovery words securely using strong RNG. For example, Electrum use
os.urandom. Other security also concern could be avoided if user don't write down their seed either on their device or cloud storage.
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It's still practical if the hackers use some Bluetooth extending antennas to extend the range of their Bluetooth connectivity to few handed meters and that's why in theory those kind of attacks can take place if the hacker is someone who knows those things. But, still these type of attacks have never took place, however it's always better to know about these because sometimes when we underestimate little probability things then that can be a reason for us to be hacked. The Bluetooth technology is very vulnerable to attacks and hackers can easily hack it with right tools.
I get your point, but
1. AFAIK any OS disable bluetooth by default.
2. Bluetooth if OP already uninstall all network driver.
I also how much antenna could help for going through thick wall or multiple walls.