The problem you describe (no text mode during boot, graphical desktop works just fine under the proprietary driver) sounds like you probably have the simplefb driver loaded without simpledrm. If you
modprobe simpledrm you should see the text console return, BUT this will also generate a second DRM interface to your video card (use
systool -c drm -p to see all of the active interfaces), which tends to cause Xorg to crash.
There’s technically no conflict between simpledrm and the proprietary NVidia driver, but the internal Xorg architecture doesn’t deal very gracefully with choosing the right DRM device, and will usually either generate a fatal error about failed modesetting, or else just segfault in xf86PlatformDeviceCheckBusID. In theory you can work around that with Option “kmsdev” in your xorg.conf, but I had uneven results. Wayland doesn’t seem to care whether you have both simpledrm and nvidia_drm loaded at the same time, but it has other limitations with the proprietary NVidia drivers.
Fortunately, you can always
rmmod simpledrm (which will blank out the text consoles), run X with no issues, and then
modprobe simpledrm again, and your text console will reappear exactly as you left it (since the data buffers are managed by simplefb; simpledrm is used only for modesetting). This is of course annoying, so you’ll probably have a better experience ditching simplefb/simpledrm and using either efifb (if booting UEFI) or vesafb for the console. Make sure you also disable “Mark VGA/VBE/EFI FB as generic system framebuffer” (CONFIG_SYSFB_SIMPLEFB), which lives under Drivers → Firmware Drivers in menuconfig rather than among the graphics driver section.
Summary of key kernel options:
CONFIG_FB_VESA and CONFIG_FB_EFI set (y or m)
CONFIG_DRM_SIMPLEDRM, CONFIG_FB_SIMPLEFB, and CONFIG_SYSFB_SIMPLEFB all unset (or at a minimum SYSFB_SIMPLEFB unset, and the simpledrm module manually unloaded or blacklisted)
Unfortunately, 5.15 and later kernels have simplefb, simpledrm ,and the SYSFB_SIMPLEFB pickup all enabled by default, and I would imagine most distributions ship their standard kernels that way, so NVidia users will have to manually fix this until Xorg (or the nvidia module) gets smarter about checking multiple DRM devices.