I also switched to AMD+AMD. The GPU support being better on AMD comes from the Open Source driver that is integrated into Linux. But there are caveats. In example if you need OpenCL or other features, it can be problematic with AMD. Plus, if you have a Nvidia card 20xx series or newer, then you can use the new Open Source driver too. And Nvidia support for Wayland and other stuff got better nowadays (just reading about it, no personal experience with current, my last Nvidia card is 1070).

While I prefer AMD gpu now, the "better support" is not really black and white.