I'm looking for a program that allows me to use my laptop as a second monitor for my desktop. My desktop is not compatible with Miracast for some reason so I've been using spacedesk but it's just too laggy. I've tried lower resolutions on the second monitor but it didn't make any difference at all. Both PCs are connected to the same network through ethernet cable so I don't think that's the problem.
Any suggestions of what may be causing this issue or any other software I can use for this?