Hopefully you realize that, in general, real-time video encoding is VERY computationally demanding.
Laptops, optimized for battery life, are not a great fit for the computationally demanding task of real-time video encoding.
lightweight small laptops are the least computationally capable devices (constrained by physics)
So you are asking for which wrench makes the best hammer, so to speak.
Apple has the new M1 mac's using a completely new compute architecture switching away from Intel CPUs, so it will take time for relevant s/w, drivers, etc be updated/optimized for that environment (could be years for certain components.. maybe/depending). Personally, I'd stick with what you know (Mac vs Linux vs Windows) and go from there
Regardless, you will have to compromise. You haven't provided enough requirements to know what, if any, laptop will suffice for you
A simple single camera and single Window/Screen capture, no chroma-keying, non-demanding workload (ie not a demanding game) sure, a properly spec'ed laptop will be fine.. probably... but... it depends...
And you haven't listed priorities like budget, expected lifetime (ex, I'd never recommend a computer with an under 4 yr life), support, etc.
In general, to offload CPU workload you can use GPU encoding to offload 'compute', you want a nVidia GPU with Turing or newer NVENC. I don't know Mac side, but clearly plenty of Mac OS OBS users, so I'm guessing Apple wrote some video drivers to make use of the AMD GPUs for H.264 encoding as AMD's own relevant drivers are reputed to be quite poor for livestreaming. On the M1, all new, so may be great... after a while... there is a thread on the dependencies (by others) for OBS Studio team to compile a M1 CPU native fully-functional build. So you are taking a risk today on a M1 and OBS.. what is your tolerance for such risk?
And look up reports of experiences with MS Surface, MB Airs etc overheating and low battery life when livestreaming. All expected with ultra-high efficiency (low-power) CPUs doing real-time video encoding. I recommend figuring out the details of your requirements (WAY more detail than you posted) and then read threads in this forum on laptops and those requirements and see what will, or often doesn't work. Most people don't have the luxury, but if you have the time and resources, it may make sense to build out your OBS setup on a powerful PC (if you aren't already very familiar with OBS Studio). That way, you can focus on getting something to work, vs trying to also understand getting OBS to work on an under-powered system, which means also optimizing the Operating System, etc. Then, once you have a working setup, move that onto test laptops and see what does/doesn't work. Then decide whether to spend more money on a more powerful laptop, or adjust your OS & OBS setup for the hardware resources available
