Sadly haven't had much luck with this issue.
I have an i9, everything is perfectly fine and relatively quiet enough until I use an external monitor.
I got this for audio production, and if I have everything plugged in (charging, mouse, keyboard, audio interface) and a full project in Ableton, I can hear the fans, but they aren't blasting my ears loud. The moment I use an external display, no matter whats open, it automatically switches to Discrete graphics and sounds like an airplane. If there was a way to disable the external graphics I'd be fine, but even Apple support is useless on helping me figure that out.