It seems like Apple has given up on desktops entirely. OSX lags unbearably when performing normal workloads. Forget about running Xcode or a CPU intensive workload, your machine will freeze due to excessive memory leaks and swapping. It is an issue at the framework level, and I say that because all software written for OSX has to use a set of common frameworks to interface with the OS itself.
People usually have success in getting newer OS versions running on formally unsupported macs.
I doubt this will work for Mojave, since I believe everything was written using Metal.