I want to build a computer that is as secure as possible for financial transactions, whether cryptocurrencies or banking.
What applications should I install to maintain maximum security (firewalld, Linux Debian, …)?
The ideal is to connect for as little time as possible to avoid invasions? What are the best practices?
Windows now has Recall as a file explorer dependancy and imho, because it cloud stores screenshots of your sessions, is not secure.
“Most Secure” is subjective. You seem to be referring to locking the box from unauthorized access. A good su password on the lockscreen goes a long way. Remote access is disabled by default so you would have to go out of your way to re-enable it. Similarly, dont install mystery programs.