@Scott-Sumner Thank you for your extensive answer.
I clearly have to do lots of reading before being able to do something one would expect to be intuitive!

@NippurDeLagash: “just position the cursor” is the very thing I shouldn’t have to do. It’s already on the line!

@Gogo-Neatza The plug-in manager infinitely insisted it needed updating.
Once I ignored it, a couple of attempts at installing this plug-in finally worked.
It appears to add two menu entries… I assumed they’d be checked entries enabling the behaviour but they’re the commands…

So then I read @Scott-Sumner’s links which all mention the plug-in too and finally a dozen steps that I need to follow to finally get this basic text editor functionality:
https://bitbucket.org/zastrowm/notepad-visualstudiolinecopy
So now I can join the throng of people who can get on with their work sensibly.

I do, however, remain in disbelief that a user should have to go to the lengths I have to simply cut and copy lines efficiently! I’ve been ignoring Notepad++ since 2004 because of this shortfall (and our fixed-width fonts not being fixed width), which leads me to ask the community again:

Would it hurt to fill that hole?

Thank you so much. That is a wonderful solution.

@Bill F,
You’re welcome.

Thanks!
I understand, but what I ask myself is when goes the “IT-Punk” busting?
In my mind, it’s a thing of graveness …
I’m very concerned.

The Edit >> Column Mode dialog just tells you how to use Column Mode (it’s probably there to inform people who don’t already know about it, or possibly because an older version of NPP actually required a toggle to enter/exit column mode)

If you highlight a region with the Alt+Mouse or Shift+Arrow, you can then immediately type (or copy/paste) in that region, and it will be inserted (or copied) in that rectangle.

If you use the Column Editor... (Alt+C), you can either input a word (just like typing) or a sequence of numbers. (In my example below, I write “something” that way, and then number from 1 to 41 by 1s)

Reported a function list issue here:

https://github.com/notepad-plus-plus/notepad-plus-plus/issues/3706

Why not write a small program in C (or your favourite programming language), to perform the conversion or download a conversion program.