The new Ryzen mobile processors should be interesting. Their GPU drivers (while not of the best code quality) are in the mainline Linux kernel. So it all should just “work”
Currently using a Renoir laptop. It's smoking fast but I had to install a bleeding edge kernel to get the display driver to work at all. That should be fixed in the next ubuntu release though.
5.10.x kernels are very stable and feature complete with AMD Ryzen Renoir - I update one almost weekly once new patch version is out on Ubuntu Kernel PPA. Here is nice script which makes the update trivial: https://github.com/pimlie/ubuntu-mainline-kernel.sh
Weird, I had no issues with the built in display on Ubuntu 20.04, but I had to update the kernel to 5.8 to get display out over USB-C to work. Now that Ubuntu 20.10 is out and uses 5.8, I'm just using that so I don't have to mess with custom, unsigned kernels.
But the slightly tweaked "old stuff" is relatively low-end - up to and including the 5700U. You'll find it in thin 'n light, budget and business laptops that will have more than enough power from a Zen 2 core. If you really absolutely need more power, you'll know it and you'll be shopping for a 5800H (or above).
If you don't know enough about CPUs to even read reviews that compare the CPU to other CPUs, then you either don't need the extra IPC of Zen 3 (and you won't notice when you use your laptop day to day) or you just... don't care.
If you care, get a 5600U/5800U or H line and it will never affect you. The laptops these come in should be priced accordingly.
