the Rapids are USB 1.1, limited to low-speed USB (125Hz).
Just to clarify: USB 1.1 is not limited to low-speed USB. It includes "Low Speed" and "Full Speed". The latter is what allows 1000 Hz polling rate.
USB 2.0 adds "High Speed" USB which is a separate mode used only for bulk data transfers -- not for the HID protocol.
But... even if a keyboard is
capable of 1000 Hz polling rate over USB, USB is a
host-controlled protocol which means that it is the host's USB hardware, driver or operating system that decides when to poll -
not the keyboard.
The keyboard does give the host a
suggestion for a polling rate, but which the host does not have to follow.
Polling rate does not say anything about the time delay required for debouncing. Debouncing is necessary for all switches that close or open electric circuits for sensing -- but not for capacitative sensing like Topre.
There are some keyboards that have 5ms debouncing delay, but I would think that higher values are more common in commercial keyboards: often something closer to 30ms.