How to fix ugly bevel in inner corner? so I feel a bit sorry about asking the probably 1000th question about the bevel modifier. Long story short, I'm having some issues with an ugly bevel in my model and I don't quite understand what's causing it:



Now, it seems to me that there might be a relation to that additional edge that I have in the green box and which I don't have in the red box. However, when manually inserting an edge on the left side like I have on the right side, it doesn't change anything (selecting both vertices, then 'F').
Also, from what I know there are no inner faces in my model.

I've checked through other bevel related questions. The closest one I could find was this one:
How to fix Beveled intersections/corners/inner edges?

Still, is there any difference for me using the bevel modifier instead of the one that works on the mesh directly? Also, I'm not quite sure what a good topology is supposed to look like.

Any ideas?
Your edge theory is right. The face the corner is in is something called an N-gon. It is usually discouraged due to several problems with its internal handling.

When you create that edge using F, the created edge does not separate the face, so the N-gon stays. In order to actually cut the face, use the Knife Tool K in Edit Mode. Select one of the vertices. You will see there is now a square and a purple line. Now click on the other vertex and hit Enter. Now, the N-gon is separated.

The N-gon gets split into more N-gons, so you might want to use the Knife Tool more to separate it into quads and triangles (which is good topology).

Your corner is now fixed.

Documentation on Knife Tool: https://docs.blender.org/manual/en/latest/modeling/meshes/editing/subdividing/knife.html