To work with multiple cursors you need to click each position with the mouse at a time holding the alt button.
And when copy text with a certain indentation or bullets - block quote, only the first line preserve it and the rest are copied without it.
Those things are something that developers use every day, and are present at several IDE or text editors like SublimeText:
For the copy and paste I installed the plugin:
For multiple line selection, I first write on VSCode or SublimeText and then paste it to Obsidian.