This conclusion seems less than optimal to me.
By condemning yourself to type 12+ character password every time you
'sudo' would really hurt accessibility and usability of your home
computer and for no good reason.
If we focus solely on your use case: a login security of a PC at
home, without remote access, then password of your sudo user could
be as short and
simple as four numbers, of course unrelated to your date of birth,
phone number, or any other easily guessable sequence of numbers,
like '1234'.
Are you speaking only about sudo or root password also?
The thing that bothers me are words: "any computer (and a fortiori any server)
connected to the Internet is regularly targeted by automated connection
attempts"
I am not tech-savvy. Can you say with 100% (90%?) confidence that there is no such thing? That home PC without SSH and whatever complicated is safe (rather safe) from "automated connection
attempts"?