modifier key for column mode?

That is a function of Visual Studio Code, and is not a feature in macOS or Apple's applications, with the exception of Preview which offers a Rectangular Selection in its Tools menu. Other advanced editors such as Sublime Text 4 also offer a column selection solution via keyboard shortcuts.

That option+shift column selection mode, as I have stated, is unique to Microsoft's Visual Studio Code design choice and is implemented exclusively in that application. It is not some feature offered by macOS or by any Apple library in macOS.

Thus, why would you expect that selection technique to work anywhere else than in the Microsoft application or another third-party application where its developers may have used Visual Studio Code to develop their application and decided to include the feature in their app?

It is not a common editing feature or two of my paid, advanced programmer's editors would feature it and they do not.

If you are referring to the Finder's view options:

cmd+1 = Icon view

cmd+2 = list view

cmd+3 = column view

cmd+4 = Gallery view

Apple's Preview application has a text selection or rectangular selection from its Tools menu and neither has a keyboard shortcut. Ordinarily, Apple does not offer this duality of selection in its other applications included with the operating system.

To get superscript or Subscript in Apple Mail... compose it in Pages others, Copy & Paste int Mail...