If you want to adjust texts that are inside rich text element first thing you would need to do is unhook that rich text from CMS ( Don’t havee it taking text from anywhere, just have it on the page as static Rich text), after that select any teext that you see inside and you willl see this:
And when it shows up as " All Paragraphs" nesteed insidee “Rich text Original” you will be able to adjust specific parameters for all elements once you select them.