Both my Macs, iMac 5k 2015 and 2015 rMBP started to miss a LOT of keypresses on Catalina. Doesn't matter if wired or wireless keyboard. Worst is the clipboard - it routinely takes up to five (!!) cmd/c presses to register. This always happens when starting typing after a pause, never in the middle of typing. I don't have any weird low-level keyboard utility. Resetting SMC and PRAM didn't fix it.