that's the theory, but in real life the macbook won't sustain 5ghz for very long at all, even less so with 8 cores. It simply can't get rid of the heat fast enough and throttles the speed to stay under thermal limits (while still toasting your balls).
The situation isn't helped by the GPU inside the same slim mbpro chassis that also gets super hot, it's particularly bad when you run mixed CPU/GPU workloads like rendering. So your desktop ends up being much faster for continuous workloads, even if on paper they both have 8-core 5ghz CPUs.
I had the 2018 6-core i9 mbpro. Got rid of it, if I were to buy a new mbpro again I would get a 4-core one.
So for GPU intensive workloads at least, it seems to make more sense to get a lower spec’d laptop for the road and an external GPU as a docking station if you need the portability.
Apple has a couple of eGPUs they made with Blackmagic (AMD RX580 - you don't want this one - and Vega 56), very slick looking and silent but unfortunately GPUs not user upgradeable and not great value for money.
You can use most tb3 eGPU enclosures and an AMD GPU of your choice. Vega64 prob the best choice now, Navi around the corner, can't use NVidia at all thanks to Apple. It'll cost you less than the official Apple eGPU and the GPU will be upgradeable
The situation isn't helped by the GPU inside the same slim mbpro chassis that also gets super hot, it's particularly bad when you run mixed CPU/GPU workloads like rendering. So your desktop ends up being much faster for continuous workloads, even if on paper they both have 8-core 5ghz CPUs.
I had the 2018 6-core i9 mbpro. Got rid of it, if I were to buy a new mbpro again I would get a 4-core one.