Most folk still boxing are trying to be compliant with "mouse-over-focus" boxing (or simple Alt-Tab) software wise...

Hardware-wise some of those that invested in multiple PCs/VMs/Multiseat_Desktops are looking into having small dedicated keyboards/keypads/keysticks for each PC. Possibly the cheapest way to do with inexpensive 10key-number-pads but a more dense option that is not too expensive is like this:

https://www.dual-boxing.com/threads/...cement-options