I don't know about Logic Pro specifically, but the only thermal throttling issues I've read people complain about pertained to the D700 GPUs, but it appears not everyone experiences that. I haven't read anything about thermal throttle issues with the CPUs. Perhaps try out a D500 unit (which seem to be the most stable) with a 6, 8, or 12 core CPU. I read posts by someone who said Logic Pro ran much worse on their 2018 Mac mini than their 2013 Mac Pro. If the MBP has issues like the mini then perhaps the Mac Pro will perform better. These are the kind of tasks the Mac Pro workstation was designed for.