I'm not sure Nvidia needs Linux 6.6+. If this change is indeed a dealbreaker, they can very well fork it at the last working version and offer it in combination with their own distro.
Even if they're unable to make significant further contributions, today's kernel is likely to work just fine for the next decade. Any improvements could happen at the hypervisor layer (because of cloud, x86_64 effectively became the new API, with the true "OS" being the cloud and its hypervisor & managed services) or userspace to not make any changes to the kernel itself and thus avoid tripping up licensing issues.
This kind of bullshit pettiness will end up making the situation worse for desktop Linux users and consumers, while enterprises reliant on Nvidia equipment in Linux-based server systems will just jump to Nvidia's fork and distro.