With Intel's issues and 3900x, 3800x, and 3700x being released, myself and another are looking for the manufactures like MSI to releasing new laptops. All web searches have yielded laptops with lower level CPUs.
Generally speaking, laptops get more energy efficient CPUs and GPUs. Those are enthusiasts/desktop CPUs that you listed. It's highly unlikely those will be put into a laptop because battery life would be horrible. That's why you see laptops listed with a U designation on the CPU.
I totally agree with qwixt. Ryzen 7 3800X is a desktop processor. Some of the Ryzen processors for laptop are Ryzen 7 3750H, Ryzen 5 3500U, etc... If you are looking for Ryzen 7 laptop, you can go with Ryzen 7 3750H laptop.
I want to upgrade my GPU, resulting in a CPU upgrade being necessary too, especially as I'm playing on 1080p 144Hz. I was thinking about buying.