>>1016428
I thought you wanted a literal popcorn wall, not drywall. Here's a shitty literal popcorn one, along with a spec and diffuse map. Anyway, you can just generate a normal map by placing an unwrapped plane in front of the geometry and baking normals with "selected to active" checked. You can only bake in cycles. Bump maps are just converted into normal maps in realtime, they are black and white heightmaps, not mostly blue like normal maps. If you want to make those manually, make a texture with 32bit channels (not 8bit) to avoid visible stepping. For drywall, I guess you can just subdivide a plane and displace it using a random noise texture. You'd want to make a material on the geometry that basically does a b&w heightmap in the direction of the "camera" plane.
You can also generate normal maps from bump maps in various software like gimp or photoshop, usually involving a plugin. Note that these "tileable" normal maps aren't quite like custom normal maps baked from sculpts and stuff, they produce somewhat incorrect shading because the surface tangents used for determining the direction of the distortion aren't strictly the ones used during baking. It's good enough for noisy textures where you don't care about accuracy. I think bump maps don't have this issue because they are calculated using existing tangents.
Also note that in blender, you need a "normal map" or "bump map" node depending on what it is, not plug the texture into the shader "normal" input directly.