ever since I updated to big Sur ive been having terrible lag as well. theres a lot new features I like with the ui and looks of the OS but when scrolling, switching apps its completely rubbish 2 month old 2020 13in macbook pro 16g Ram and i7 using a dell 27in S2719DGF currently overclocking the monitor @155hz and its crazy choppy and raggidy when I switch between apps and scrolling through pdfs. especially when using goodnotes, while scrolling through notes it looks like im using a 1990s hp