FYI: You can put a low-profile mechanical keyboard on top of your MacBook built-in keyboard and it works great.

I use the Keychron K1 Pro with Brown Gateron switches. It's an 80% (ten-key-less / TKL). I needed this one because I use the right shift key a lot and it has a full-size one whereas the 75% is shortened.

You get used to the slightly different layout very quickly. You might swap back and forth a bit but when you go to bed you will start dreaming about typing on it. You will even enjoy doing typing races just to press the keys.

Another new one just released is the NuPhy Air75V2.

It's a real addiction!