Uh... Just buy an off the shelf model. Keychron and Leopold make good keyboards for example. I'm sure others will post other recommendations, but what's your budget, which continent do you need it shipped to? Maybe you have local tech shops that sell computer peripherals.
Mechanical Keyboards
Are you addicted to the clicking sounds of your beautiful and impressive mechanical keyboard?
If so, this community is for you!
Here you can discuss everything about mechanical keyboards (and only mechanical keyboards).
Banner by Jay Zhang on Unsplash
Yeah, I'm really happy with my Leopold which I've been using for the past 3 months. I used to have Unicomp before that; and while the typing feel was a little better than the brown switches I currently have on the Leopold, its build quality was lower, and eventually it just died on me thanks to what I later found out was a notoriously failure-prone controller they used to use back then. I'm told that Unicomp's build quality has improved a lot since then.
.... though the frustrating thing is that I was able to get the Unicomp only because I was living in the US at the time; and the Leopold I got thanks to relatives in S. Korea. Where I live, 'mechanical keyboard' is treated like a synonym for 'gamer keyboard', and all the BS associated with that.
So excellent off the shelf brands exist, though one has to do some local research first.
Budget: Undecided. No hard limit, as long as it's reasonable. maybe 150-200 usd equivalent.
Location: Norway.
Keychron looks like they have what I'm after. The Q5 looks nice.
Look at Keychron. Wide selection of boards. Pretty solid build quality and reasonably priced!
Second this. I was so happy I bought a second one for work.
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.
MX mechanical support ISO and fullsize as well
Keychron has the K10 (full size) and K13 (TKL footprint with most of the numpad) in wireless ISO.