A split keyboard by ak66666 with thumb keys raised above the rest.
KBD.news Published January 7, 2022
I've seen several Japanese DIY keyboards with MX switches paired with low-profile thumb keys – that's how I use my Azimuth too.
However, fellow Redditor ak66666 came up with a design the other way around: raising the thumb keys.
It must be the difference in our working environments (desk/chair/armrest height) and the way we hold our hands. (When I slowly lower my fully relaxed hand above my desk, the first finger touching the tabletop is my thumb.)
Anyway, this is something you can contemplate when designing your own physical layout.