Storyline 360 Tabbing and Screen Readers

I'm acquainted with changing the tab order in slides and slide masters, and disabling/removing items that I don't want tabbed to. But one thing I'm not certain about is the overall tabbing behavior along with using a screen reader.

I recall that in HTML, tabbing on a web page shows a focus rectangle around interactive objects, but not around blocks of text on the page (since they're not interactive).

In Storyline, though, does one have to keep blocks of text tabable in order for them to be discovered and read by screen readers? For example, if I have 2 blocks of text and a custom NEXT button, is this the ideal?

Tab 1: slide title ("Intro to Plant Music")
Tab 2: paragraph of text ("Plants can play many instruments..."
Tab 3: NEXT button ("Next")

(I would remove all tabbing for things such as backgrounds, lines, visual elements that are not content, etc.)

I'm mainly asking because, in my mind, I think of the tabs to the text as "in the way" and want to be able to tab directly to the NEXT button. I have not tested with a screen reader, and want to be sure that audience is handled accordingly.

So, should every thing be tabable, both A) navigable/interactive items as well as B) all content (text, images with alt text, etc.)?

Thanks for your thoughts and input!