Big Sur 11.5.1 keystroke delays

Since installing Big Sur 11.5.1 there are many occasions when keystrokes don't get recognized and the beach ball shows up for a second or two before the keystroke is displayed. This happens in several apps; the most frustrating being in Mac mail. I can be typing a new email and new keystrokes don't get displayed sporadically, and the beach ball spins AFTER the keystroke is not displayed for a second or so. This also happens in other apps - Chrome, MS Word etc.

Also, when using the touch unlock, the same thing happens: no response to a finger touch fo 3 or 4 seconds. Usually requires 2 or 3 attempts to unlock with touch.

None of this happened with earlier Big Sur versions. This is on a 2020 Intel 16GB Macbook Pro.