it's far easier to manage hardware resources on windows than it is on mac, so if you want it whisper quiet it might be better to install windows with bootcamp or similar, but there are a few things you can do:

1) disable turboboost, it's not possible to adjust max clock frequency on macOs, but it is possible to disable the turboboost feature which goes a long way to keep it quiet and cool
rugarciap.com/turbo-boost-switcher-for-os-x/

2) edit 'alpha centauri.ini', on my mac it is located here:
Users/simonolesen/Library/Application Support/GOG.com/Sid Meier's Alpha Centauri/Alpha Centauri.Ini

3) change wine display options, on my mac that tool is located here:
Volumes/macOsExtended/games/Sid Meier's Alpha Centauri Planetary Pack.app/Wineskin.app

4) limiting process resources is not directly possible on mac like it is on linux or windows, but you can use tools to repeatedly request a process to wait, more info here:
apple.stackexchange.com/questions/24998/can-i-manually-limit-the-cpu-used-by-a-process

I'm trying to figure out how to make it run picture perfect too!
so far it's drastically better than the default install on my mbp 2015 15" with m370x gpu, but after changing things I have the problem that I have to press esc before a wonder movie finishes otherwise the screen resizes incorrectly which is annoying

good luck, if you find good resources post them here ;D