Why is my light rendering with fragments?

Let me begin by saying that I am fairly new to UE.
I understand that there are a million tutorials and forum posts out there and there might be one with the answer to this problem. However, finding that one post proves next to impossible. So please forgive me for asking what might be an obvious or already answered question, I have spent two days trying to find the answer somewhere else…

I have set up lighting in my level and so far I have only been using standard lights.
Then I stumbled across Light Profiles, which I thought would be perfect for my goal.

However, my lights seem to be rendering in a very ugly way.
It looks nothing like the light when editing the level.

What am I doing wrong?
What information do you need to help me with these ones?

You want to increase lightmap resolution for your wall meshes and make sure your lighting quality is set as high as possible in the build settings and in the world settings of your level reduce the Static Lighting Level Scale to something lower than 1 (0.1 is good but will increase the build time).

Also make sure your lightmap UV’s aren’t overlapping. I don’t remember about 4.21 but newer versions can unwrap UV’s for you from the static mesh editor.