Removing middle edge without deleting face

Hi. I saw a thread on here about removing edges without deleting the faces and I was hoping to find an answer to my issue on there but unfortunately I did not. Basically my issue is I am 3D printing what basically is 1/4 of a circle made into a solid “tray form”. There are holes made on the side with the boolean modifier, and those holes are important because they are where the bolts will go through; basically, we’re printing this four times, bolting them together, and making a large 3D printed disc that will have an emblem on it. However, when I add the bolt holes, it added an edge that goes around the middle which apparently messed up the 3D printing process when we first test printed the object, so it needs to be removed. How may I remove that edge without deleting the faces? Even when the face is deleted and I add the face again to replace it, it ends up covering that bolt hole I made. I will supply a .Blend file so it makes more sense.

janice 3 end.blend (483 KB)

How may I remove that edge without deleting the faces?
You cannot. The mesh structure will not permit faces to have holes in them so you can only choose how that hole is connected to the outside of the face.

For a start to ensure you get the model exported in the way you want you should not have all those ngons (faces > 4 sides). When the file is exported, depending on the format, it may be triangulated (such as with .stl files). If you have the ngon you are not deciding how that face gets triangulated, you are relying on blender to decide (maybe badly) for you.

which apparently messed up the 3D printing process when we first test printed the object,
In what way ?

Where the edge is on the model, the 3d printer prints a strip that does not stick to the rest of the model.

The 3D printer prints a strip where the edge is that does not stick to the rest of the model.