How do I determine keyword search volume using AdWords?

I'm looking to start an SEO project. Currently, I have a list of around 100 keywords. However, many of them are outdated, so I want to test the current search volume for these keywords. What's the best way to do this through Google AdWords? I've tried using the Keyword Planner, but it seems highly inaccurate. I'm assuming that running some PPC campaigns might provide a more accurate insight into the search volume these keywords receive.

Has anyone had experience with this? What's the best approach?

Maybe start with a small budget and target all 100 keywords, ensuring you set the campaign to show ads as often as possible ('Accelerated' ad delivery). Tehn monitor the impressions and click-through rates closely over a short period, such as a week or two. This will give you a more precise idea of search volume and user interest