It doesn’t help that the walls aren’t square to each other and that wall isn’t parallel to the red axis
Are the walls from your imported CAD file?
One thing that gets in the way of accurate modeling is having Length Snapping turned on in Model Info>Units.
The best advice is to turn off Length Snapping for your default template(s) and my preference is to set Precision as high as it will go for the selected units while I’m modeling. I wouldn’t normally dimension anything in 64ths but I want to see them if they occur so I can deal with them ASAP.
You’ll notice there are no top faces on some of your walls. This is due to some bad and missing geometry. This is another thing that’s very hard to detect with the style you have chosen but it’s very clear when back face color is different from front face color. When you zoom in close to the top of the wall we’ve been talking about you can see the gap between the inside face and the top.
As to the back face color being different from the front, it helps to identify problems like holes and other missing faces. Having face orientations correct also makes adding materials easier and if you plan to use a rendering program, many of them won’t render back faces even if those faces have materials applied to them. You might not be interested in 3D printing your model but face orientation tells the 3D printer which side of a face is the print media and which side is air.
The style you have set is a nice display style but between the face colors, the light gray edge color and the extensions being turned on, it’s not a great style for modeling with accuracy or precision.