I’ve been griping over this for years now. I get pretty bad RSI so like using a split mechanical keyboard for coding, but I also use long/complex passwords so I like using Touch ID too. It dumbfounds me that you can’t get a Touch ID pad or even a numpad with Touch ID to sit next to aftermarket keyboards.
I bought a used Magic Keyboard on eBay for about $50 to sit within reach of my mechanical keyboard. Considered mounting it under my desk but haven’t bothered yet.