I just answered something similar over here:
Check the link in that post for feature support based on OS and GPU.
Yes, all 2070 and 2080 GPUs are hard to cool and you will definitely hear the fans. But the new 16" Macbook also ramps those fans up much more than any Macbook before it (refer to all the reviews of it for video editors). I think across the board you are going to be dealing with hot, fan-spinning laptops when you are looking at a thin chassis with a top-speced GPUs, it’s just physics.
If it’s going to be your only machine, it’s tough call. But it also depends greatly on how you plan on using TouchDesigner. If you are performing, one laptop can do everything for you and you only need one machine. If you’re doing installation work, eventually you’ll be building/buying machines (likely desktops) to leave at the installation venue (you’re not going to leave your daily-driver laptop there for days, right?). In this case your choice of mobile platform opens up considerably.