Oh, I begin to see- though it does sound like what you want, is exactly what ProBuilder does, and does with standard static meshes. (or dynamic, should you want them to be so)
In PB, you are always building just a standard, regular, mesh. No BSP/brushes/etc.
You can, as mentioned simply create a cube (or other shape, including procedural like stairs/arch/etc), assign materials per-face (“side”), then drag the sides into any shape. You can continue to make windows, doors, extrude, duplicate, etc. All this, and more, no problem in PB.
At the same time, yes, the UVs are being auto-generated to tile cleanly. You can also edit that auto-tiling (ie, offset, rotation, scale, flip, etc), similar to the brush-based methods.
Additionally, you can dig in and do a full UV Unwrap with PB, if you like. You can also swap between manual UVs (unwrap) and auto UVs (brush-style, auto generated), on the fly, per-face.
Correct me if wrong, but I think PB does exactly what you are asking for, and then some?