Moving lights can be moved in game perfectly without problems but if you put too many in the game will run badly, the other 2 doesn’t make the game run slowly but they don’t work good if they move in the game
Movable lights–you need to move or rotate the light during the game, and you need the light to cast dynamic shadows, this gives the worst performance, ideally you only have your directional light as movable
Stationary Lights–you need to animate the color or intensity of the light, and the light needs to affect dynamic objects, but the light itself is not moving or rotating, can only have 4 lights overlapping an area
Static lights–the light is not being animated in any way and does not need to affect any dynamic objects, you can use as many of these as you want it will only increase lighting build time but will have good real time performance
This is normal. This happens with most engines that bake lighting, it’s just something that can’t be avoided. What we devs do is build environments around these limitations. For example, in your case, I would make that wall one single mesh that shares a lightmap across the surface that will be on the golden path of your game. Another thing we will do, among others, is to create some sort of natural separation at that point, for example maybe there’s a pipe that goes down the wall at that point or maybe some facade detail, different texture at intersection point, decal, anything.
This is happening because the light is baking data into a texture, called a lightmap and it’s perfectly normal.
Then create a single large piece that doesn’t have seams so that there is one continuous lightmap across the mesh. This is almost like asking “why can’t I make a game with characters that are each 10 million triangles”; game engines have come a long way, but they’re still game engines and have limitations. One of the least talked about skills of the modern game developer, is solving problems like these and coming up with creative solutions to get around these limitations.