Remesh is a static operation that globally generates new topology across your entire sculpture when the button is clicked.
Dynamic Topology generates new topology only under your brush as you sculpt.
Personally I don’t like the global, static nature of remesh. I find that dynamic topology gives the user much more specific control.
As for follow-up courses, I would recommend these:
- Intro to Character Modeling
- Sculpting the Wrangler
*Note that they’re recorded with pre-2.8 Blender but the concepts are still entirely relevant.