As I've overlooked the existence of #FreeBSD #ports graphics/drm-latest-kmod (now at 6.9) until yesterday, there were no corresponding #nvidia ones.
Now I've filed Bug290262

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=290262

and opened corresponding review D53128

https://reviews.freebsd.org/D53128

to add graphics/nvidia-drm-latest-kmod and graphics/nvidia-drm-latest-kmod-devel.
Now the review is accepted and waiting for land.