For my job, I often have to share my screen for lengthy calls.
As my setup, I use an LG 27″ UD58 4K screen and a 2015 Macbook Pro.
Now, this screen is not exactly ideal to show designs.
The people on the receiving end might be using a 15″ laptops, so the image they receive will be too small.
Even worse, because of the massive resolution, screen sharing is processor intensive and things might be choppy because you have to upload a massive image as well.
What I would sometimes do to fix these issues is to detach my screen and present from my laptop only specifically for the call, but since this is an everyday occurrence, this is quite annoying.
I found a solution in setting a shortcut to change my resolution using SwitchResX. With this small tool I set a shortcut so that ⌘+F6 becomes a switch to change from the native 3840×2160 resolution to a more streamable 1080p. Another shortcut brings me back to my native resolution.