Thanks. The equivalent on macOS is holding down Shift+Option while selecting with the mouse. However, these keyboard shortcuts aren’t currently documented at: Keyboard shortcuts for editing - Obsidian Help – nor do I see them under Settings/Options > Hotkeys.
For keyboard+mouse, this matches what I see for Column Selection in Visual Studio Code, but it also allows column selection with just the keyboard. It’s Shift-Option-Command + arrow keys in VS Code, which I haven’t been able to get working in Obsidian (v1.2.2). Visual Studio Code also has a menu option to switch to Column Selection Mode, which may be easier for users to use.
If you are editing a fair number of lines of text, round-tripping through Visual Studio Code may be the best option right now. It also has multiple cursor support (hold Option-Command + arrows on macOS) as another way to make changes quickly.
My example use case is taking notes on an hour long YouTube video which has a table of contents with play times, but I don’t need some of that info. A few quick edits and I have the basis of adding notes on each topic (there are 44).