Most webcams use USB UVC protocol which is supported on Linux. I have a Logitech Brio 4K webcam I use for doing YouTube videos (with OBS) and I have some cheaper Redragon webcam I use for video calls. Both work great. I also just picked up a 4K HDMI USB capture device that also uses UVC and it works just fine as well.

For graphics card, AMD is best. Intel is getting there as well. NVIDIA works but the drivers are proprietary, out of kernel, outside of Mesa, and painful to maintain. Do not recomment NVIDIA. I personally use an Intel Arc A770 in my main PC and it works fine for the games I play EXCEPT that Yuzu emulator runs like absolute crap with it, so this past week I swapped it out for my older AMD RX580 to play TOTK at 60fps.