Closed source drivers are not really the issue. But competing graphics APIs are. With the move to Wayland open graphics drivers were updated to support the GBM graphics API which if one window manager wants to support then it gains support for all graphics drivers that use that api. But nvidia created its own api, eglstreams that to support required all window managers to write extra code for. Some refused to do that or took a long time to do.which gave shoddy nvidia support.
Some did support nvidia slowly, but then nvidia also switched to support the same api as everyone else (poorly at first but I assume it has improved over the years). Nvidia have also partly released their drivers as open source which has also helped.