I am suffering from this problem as well (2020 Dell XPS 13", Ubuntu LTS 20.04), even after applying the fix at https://www.displaylink.org/forum/showthread.php?t=67148. HOWEVER - I have found that if I mirror my displays (laptop built-in + external HP2511X vis DVI), the lag disappears. This is true even when connected via an external USB 3.0 hub, so at least I can use my external mouse/KB at the same time as enjoying the larger desktop.
I am suffering from this problem as well (2020 Dell XPS 13", Ubuntu LTS 20.04), even after applying the fix at https:/ /www.displaylin k.org/forum/ showthread. php?t=67148. HOWEVER - I have found that if I mirror my displays (laptop built-in + external HP2511X vis DVI), the lag disappears. This is true even when connected via an external USB 3.0 hub, so at least I can use my external mouse/KB at the same time as enjoying the larger desktop.