Keyboard incessantly repeats letters
After upgrading to Big Sur, my keyboard began repeating several of the letters I type and despite tweaking the key repeat and delay repeat tools in system preferences, I can't get it to stop unless I turn it off and then it becomes so slow it drives me about as bonkers as the original problem does.
It isn't every key, but only several, L being one of them.
I've cleaned the keyboard and googled myself silly and nothing so far works.
Help, please!