First thing I learned attempting the same is that lid open vs closed are two very different situations in terms of thermals.
But overall without aggressive throttling these devices work a maximum of half an hour before the components get saturated with heat and performance tanks.
Yup. Gaming laptops with dedicated GPUs tend to fare better on this because internally the CPU and GPU is often bridged with a heat pipe and shared cooling
So thermals are specd for both running at same time but you only need CPU for home server so shouldn’t throttle