I dug up an old post by Marco Arment complaining about dGPU and fan issues on his 2011 15"
Yep, thermal issue have plagued MBPs since at least the early-mid 2000s. While one can do pro work on them, one of my criteria for a pro machine is the ability to run whatever necessary, 24x7, w/o damaging the machine. MBPs have failed in this regard for a long, long time.
I'm finally hoping (what's that thing about doing something again and again, and expecting different results?), that if I go with a base model 13" w base CPU and no dedicated GPU (and adding an eGPU) that my dreams might be realized. I'm guessing with the lower thermal levels of the new CPUs and little added GPU heat, it might be able to finally do it. And, at least if it gets too hot in there, it will probably fail more gracefully than cooking the GPU (as it's integrated, probably with same thermal protection). Also, with SSDs, the storage is probably a bit more heat-robust.
I should probably give up on the dream, and just have two dedicated machines... but, like I said above, I keep trying.