Do you want to elaborate your exact issues with the risk of ledger exit scamming ?
Like, what scenario are you afraid of exactly ?

One of the most secure options would probably be to buy a new laptop, remove each wireless interface (wifi, bluetooth, ... ) and install a linux distro on it.
Then use any preferred desktop wallet (e.g. electrum) to store your private keys.

You just need to make sure that this computer never goes online and that you never plug in any device/storage which has been connected to an online computer once.

You'll need to move unsigned and signed transactions between your online and your cold storage computer.
Using webcams would be an option.

But you know.. there might be an exploit in the QR code scanner. So effectively, you are never 100% secure.
However, using a dedicated computer just for storing the private keys is definitely one of the most secure options.