Should my lead form ask qualifying questions if I run paid ads?

Yes, that can be a good reason to have several questions. With paid ads you do not want to fire the ad pixel unless the person meets certain criteria, so that only qualified leads are sent to the ad platform. This reduces wasted ad spend, even if the cost per click rises.

Still make the form less intimidating: hide the questions or split them into a two step form. Fewer visible fields means more people start filling it out.