Hello @mstranovsky,
Why yes there is. Right click on your dynamic text in the contents pane (left side) and select properties. Select text properties and scroll down to callout. Then select point size.
You can also select the size of your dynamic text when you scroll up.
Here's the help article on text: https://pro.arcgis.com/en/pro-app/latest/help/layouts/text.htm#:~:text=To%20make%20changes%20to%20th....
Be sure to select a reference scale for your map, so your sizing is relative to the RF (relative fraction) scale of the map you present for viewing. That's under map frame properties, which is also in the contents pane.
By the way, most people over age 45 can't see any text less than 12 point without eye strain, so if that's your audience and they're paying your salary, be nice to them.
Woo hoo - Hope that provides you with some fun exploring.
