Checked on another p/c and discovered that the new Nvidia drivers automatically add the ‘nosimplefb=1’ bit to the boot line.
The way I understand it, it will be safe to keep that added to your boot line for as long as you use the same nvidia graphics driver on Tumbleweed.
I’m permanently adding it now (either via grub config or yast bootloader config) even if it becomes redundant in the future.