i think you might overestimate the building part.
If you get a barebones board with a hotwap PCB you have to screw in stabilizers for all keys larger than 2u (=2 keys) - Shift, Enter, Backspace and Space. Since you can’t be arsed, screw lubing them. Just screw them in, takes 3 minutes.
Then, place all the switches on Plate and PCB and since they’re hotswap you just press them in.
Then place like 8 gaskets or screws, drop on your PCB-Plate-Switch-Sandwitch, screw together top and bottom with 4 more screws.
When you’re done, mount the caps, also just pop them in place.
That’s it. I reckon it’s about as much work as a 10$ Lego set.
But going prebuilt is far easier of course: Unpack, plug in, done. If you get a hotswap you can change switches later on if you fancy.
Monacokeys from Munich sells XDA White on Black. Only in German though.
But you could hit 'em up on discord and ask if they are able to source you an US layout or point you to a shop that has those in stock.
https://discord.gg/6MH5KpjK