UE5 AI Characters + AI Controllers
Three steps:
1) Make a Nav Mesh covering the area you want monsters to path around in
2) Make a new Character and set its mesh to some interesting skeletal mesh and AI controller to the thing you make in Step 3
3) Make a new blueprint that inherits from "AI Controller" and then write code using the Simple Move To nodes in blueprints to have it move the monster around the world.