There are numerous tutorials out there on how to animate textures, normal-maps are no difference, here is one tutorial I recommend that still works, it transforms the UV of the mesh dynamically based on a stated game-property value.
Hello and welcome to BlenderStackExchange. I assume you downloaded and tried running a UPBGE 0.3x release? The latest version that is built on is Blender 3.0x, which may not be as compatibility to Blender 2.91.0 releases unfortunately. Unless you are attempting to import those Blender 2.91.0 models into say, a legacy UPBGE version such as UPBGE 0.25b, I'd ...