Thank you ActionableMango for your answer. Is this (https://github.com/Floris497/mac-pixel-clock-patch-V2) what you are referring to?
It says that this patch resolves resolution on older macs. But can't see anything about refresh rate. Do you think it is implied?
Yes, that patch removes artificial pixel clock limitations from MacOS. Removing that limitation opens up the possibility for higher resolutions and/or refresh rate, assuming the hardware can support it.
Keep in mind that I said "might" work--even with the OS pixel clock limit removed, there's still a hardware pixel clock limit and I don't know what the HD4000 pixel clock limit is.