I’m using Apple macOS so sorry can’t help with Microsoft Windows.
Not sure if it’s any help but if you can’t use CTRL+V, can you use the Publii Copy and Paste commands in the Edit menu?
Most editors of course expect content to be input using the editor either by typing or copy and paste. In Publii, you have 3 editor choices: WYSIWYG, Block, and Markdown. I’m not sure if it’s possible to add a custom button to the WYSIWYG editor to maybe import or get text onto a page in a different way (even if possible, sounds like it could be a bit tricky to maintain its state over subsequent Publii upgrades, etc., 🙂