They do not. It was suggested that ones with flavour containing diacetyl could cause popcorn lung. However, cigarettes contain a lot more diacetyl, and popcorn lung is not one of the many health risks of smoking. There is some anecdotal connection between diacetyl and popcorn lung, but far from a scientific consensus.

Thanks! Sorry, forgot to make sure the links to the model was posted. Now they are.

STL files and FreeCAD document posted on Printables: https://www.printables.com/model/741845-parametric-monitor-stand-feet

And GitHub: https://github.com/funkyfourier/monitorstandfeet/

I did not, it is still in its original case. In the new case there is a holder for a cylindrical li-ion battery. Have not dared trying it yet, though, but pretty sure it will work.

Link to the model: https://www.printables.com/model/652195-3d-printable-case-for-the-keychron-k8-pro-keyboard