Photoshop 22 (=Photoshop 2021...) terribly slow

Every action causes the 'beach ball' to roll. Even a brush stroke.

I am on a Mac Pro, 96 gB / 4tB SSD / 16 core 3.2gHz / AMD Radeon Pro Vega II 32gB.

Photoshop 2020 (= Photoshop 21...) works fine.