That’s the right one. The message is simple: Avoid NVidia if you can, choose AMD if possible, or Intel onboard gfx for less demanding stuff on Linux. On Windows, Intel is a dumpster fire.
That’s a completely outdated page from ancient times. It is not linked at all from our Webpage, and should be inaccessible, so it is unclear how you stumbled over that one.
See almost the same question asked and answered only a few days earlier. Probably fine, in general, with graphics and timing on Linux, but no guarantees. I wouldn’t choose Ubuntu 18.04 any more for a fresh install, 20.04.2 LTS is the most recent stable Ubuntu release. My PC has AMD Ryzen onboard graphics and runs perfectly under Ubuntu 20.04.2 LTS atm. Most of my modern machines only have 8GB, and my main laptop and RaspberryPi run PTB fine under Linux with 4GB, and even 1GB.
Any potentially more detailed advice only comes with priority support, as does more timely advice.