About the scaling issue, there will be some apps that won't scale properly to 4k. But in the worse case in these situations (assuming it's only occasional) you can set windows to 1080p and let the monitor scale to 4k.
As long as the monitor is just doing nearest neighbour scaling it should look just like a 1080 screen.
As long as the monitor is just doing nearest neighbour scaling it should look just like a 1080 screen.