I also require the 580 drivers on a laptop. They are available in 26.1 but the nvidia-settings app is only compatible with the 590 drivers, so I can't really use it. So for now I can only use integrated graphics. That's not bad for me, but 3d acceleration is limited with that.
My laptop has a GTX 1050 GPU, and UHD 630 for Intel iGPU. So ya, I'm limited to the 580 for Nvidia.
From what I've read in the FreeBSD forums, people with older hardware running on 15 are having issues using older GPU drivers.
This has me thinking I should spend a few days installing FreeBSD instead... Would take me back to my Slackware Linux era in 1998-early 2000's! Spent so much time setting that up, but I got a lot of help from some Linux nerds where I lived.
On the flip side, an older laptop of mine from 2012 runs 26.1 competently! Zero issues there...