New player looking for an RTS with single player tower defense

I played lots of RTS games in my childhood like Empire Earth, Knights & Merchants, Impossible Creatures, Submarine Titans, etc, and after many long years I want to jump back in. But Im a noob and my favorite way to play is turtling up with a bunch of turrets, slowly growing my army behind walls.

Does Age of Empires 2 DE or Age of Mythology Retold have custom tower defense-like scenarios I can easily browse, download, and play solo? Which of these two games would you recommend for this?