From an other old computer geek (have taught software applications since more than 3 decades), a recommendation., probably unwanted. You could benefit a lot, and spare a lot of time from some personal training.
I mentioned the Assets libraries which I use mainly to transfer easily shared actions and user variables between projects. Lot of the assets you mention can be embedded in the Theme by using the master slides. You have some links to my blog now, you'll find a lot of useful information there. From ChatGPT I learned that this blog may be a unique resource for Shared action and Themes. Please take also some time to explore Captivate's Timeline, because it causes the biggest amount of problems to new Captivate users. This article has over 70K views:
https://blog.lilybiri.com/pausing-captivates-timeline
As for quizzing, this is a link to one of the posts in a basic course (I don't have a lot of basics on the blog):
https://blog.lilybiri.com/quiz-basics-2-submit-process
To avoid you lot of headaches, avoid creating responsive projects. They are only really needed if you expect the learners to access the course mainly on smart phones. But you know also that this may not be the best device for real learning. Responsive projects in Captivate do have a lot of limitations which will for sure cause you frustrations. You can publish any course to Scalable HTML output, which makes them accessible in any browser, desktop or mobile, but only in landscape mode.