I use a displaylink device (HP portreplicator 3005pr) to switch between Ubuntu desktop and windows laptop. Two monitors.
Issue with the desktop: clean install Ubuntu 20.04 and following displaylinks installation instructions for 5.3.1 driver. Works fine with one monitor connected to video out on the desktop and one one displaylink device.
Both on the displaylink device mouse movement okay, but reactions on actions to slow, serveral seconds (>5), reaction on typing also lagging behind.
Second try: clean install Ubuntu 20.04 and following display link instructions, but instead of libdrm-dev I used the non dev version. same behaviour, but reactions speed now increased tot a lag of 3 seconds when alle displays are on the displaylink device.
Video Both on Displaylink
Video One on Displaylink On on desktop video out