For GPU: AMD (but not _too_ cutting edge is the easy answer here).
Any of the Radeon 6000 series will work well out of the box with recent open source kernels.
CPU wize Intel/AMD does not matter.
CPU wize Intel/AMD does not matter.
If you are comfortable with building the drivers (Kernel/Mesa) from yourself, then cutting edge GPUs are usually fine too. E.g. Navi 2 support was all there on release day but perhaps not yet in all distros. Not saying that this should be reasonable for everyone but we are on a tech forum.