Good evening, @lcarter ...
Happy New Year! Sorry to see that your question has been sitting out here for quite a while without a response. By chance, do you have Canvas Studio? If so, you could load your lecture videos through there, and you can choose whether or not you would allow end users to download the videos. How do I embed Canvas Studio media in a course? - Canvas Community
Or, if you had a YouTube account, you could upload your videos to YouTube, and then make those videos "unlisted" where they would need to have a link to view the video. Unlisted videos still can be embedded in your course pages, too. And as far as downloading videos off of YouTube, I'm pretty sure that goes against the Terms of Service from YouTube.
I hope this will be of some help to you. Sing out if you have any other questions...thanks! Take care, and be well.