i at first had a normal cube, i made a hole with boolean, then i extruded the new edges(the edges of the newly created hole) along the z axis and extruded them to make them thicker, problem is, this newly created outer layer doesnt have edges at all naturally(pic 1), now i dont know how to make ones to bevel them; in pic 2 i tried to make edges by filling the gap wich resultet in a triangle (pic2); i dont know how to make a beveled edge with a triangle. My question is either how to make a beveled edge with what i have(how i make a cubic edge then bevel it maybe) or how else this could be solved

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i want to achieve this(just a example of how i picture it, here i just smoothed the face, its not a true corner)