Those secure elements are already backdoored by nsa.
If a device is being made to store bitcoin, then they have all incentive to back door it.

Again, air gap is also a data, a malware can still be transmitted via air gap.

I have two laptops just dedicated for that purpose. And I use usb and I format it after each transfer.

But again if everyone knows what I’m going to do with a device be it generic laptop or hww, the incentive is to back door it.