Originally Posted by
LilDrunkenSmurf
The M1 mac only supports a single extended display, so a dock would sort of help, but you could only use the LG monitor (I have no idea on how to use the iMac as a monitor).
I would suggest just a simple USB-C dongle with an HDMI output or something, and tie into the second input on the extended monitor, and maybe a USB-switcher for the mouse/keyboard, if they're wired. You can buy 3rd party docks that will let you use more monitors, but it really abuses the CPU, and you need to install DisplayLink software, which will require admin rights.