No worries Wade - not too late at all
It’s good to avoid uploading large video files in the Pressbooks Media Library mainly so that the file size of export formats like EPUB can stay low (ensuring that readers with poor connectivity or limited bandwidth can still access the books).
Linking to or embedding videos hosted on a third-party platform like YouTube, Vimeo, or other is ideally the best option. For videos licensed All Rights Reserved, you could still host them on these platforms but under the appropriate license, or explore whether they can be unlisted videos (accessible only with a direct link). I’m not sure whether the authors/video creators will have a preference over this versus a dedicated server (or if these files are already hosted elsewhere that you could point to). I’m afraid for now, these are the only 2 options coming to mind, but I’ll continue to have a think and we can chat more tomorrow.