The thing about laptops is that they tend to have processors with lower base speeds, like 1 to 1.5GHz. Still, a good Core I7 (10th gen or later) should be able to handle 16 channel audio. I'm running a 3.2GHz 4th Gen I5 and can easily record 8 channels using Reaper. I do 1080 video rendering on the same machine with 12GB RAM and the Intel onboard graphics. Sure my frames per second aren't the greatest, but in my case time ISN'T money. I can set it up, start the render and go have lunch or cut the grass. It's all done when I come back. BTW, I have a TB SSD and a 2TB hard drive. The system (Lenovo H50) is about 8 yrs old but still hums along fine.
If you're going to be doing 4K video, then you probably want to stay away from a laptop. A desktop with something like a I7-12700K or I7-13700K should easily do the recordings, has a higher base speed (2.7 or 2.5GHz with 16 cores) and the UHD graphics will do the video encoding but may be a bit slower to render than a good video card. Of course that is something you can always add later if you find the need.
One issue you run into is balancing the high temps and fan requirements of high performance video cards with the noise level. Video cards can pull from 100 to 300 watts of power and that means they need airflow. Dual and triple fans are the norm. Plus a really good video card can run $300 to 1000.
For stuff like this, I prefer to have a small tower, where I can add extra SSD/hard drives and memory easily. Plus you'll have extra USB ports for things like external backup hard drives (yeah, you really ought to be doing this), you mouse and keyboard, and interface. Some laptops only come with 2 USB ports, and you run out really fast. Better to have 8 ports and need 4 than to have 2 ports and have to use a USB hub that may not play well with your interface.
Are you looking for an off the shelf prebuilt system, or planning to assemble yourself (or have it custom built)?