Also, if you have 12BTC on a software wallet my advice inmediately changes to: Buy a hardware wallet NOW!
What's wrong with a software wallet? Mine is password protected, stored in a veracrypt volume, which is stored on my encrypted /home partition, and included in several backups stored in different air-gaped locations and only ever connected one at a time. (and most importantly, I'm not running a toy operating system.)
Well, you are describing it perfectly. I can have better security with my hardware wallet without needing any special security measures. I could even use it on "public" computer.
I say "better security" because no matter how many layers of encryption you may be using... at some time you would need your computer to access the wallet in "plaintext" to sign the transactions and that opens an attack vector.
It's much better to have the signing be done inside a specialized hardware....
Plus it is amazingly more convenient to use.