What is the correct font size to be used in Storyline?

What is the best standard font size to be used in Storyline for:

1. Slide title (heading)
2. Subtitle
3. Body text

I feel like our team is using too large of a font size because many are used to creating PPT presentations. Although I was researching and found this article: https://learnui.design/blog/mobile-desktop-website-font-size-guidelines.html

I was shocked that it recommends 16px! That is huge and takes up a lot of real estate on a slide. Your feedback will be greatly appreciated!