I have a super problem, I'm a beginner in blender, about 2 weeks, and I wanted to make an arch, but only it should be filled and with rounded edges, I was able to make the arch itself, but there were problems with the rounding. I just created an arch point by point, filled it inside and did an extrusion, everything would be fine, but now I need to somehow round off the edges and here everything is not going according to plan, I don't know if there is any normal way to do this, then what I ended up with when using the surface subdivision modifier - it's just awful, it's impossible to do uv, please help me, I searched the entire Internet and did not find anything. I also tried to use bevel along the edges, but nothing worked, since there is no geometry in the filled place.
I'm assuming you want to smooth out the mesh. To do that you can do shade smooth, which can be accessed by selecting the mesh and 2 finger clicking, which will give you a menu that has shade smooth as an option. You can also search "shade smooth" in the search menu (relatively new as well so not sure what it's called).