the devs have introduced a new experimental feature in Standalone 2025.1 named Octane Server: There is still a lot of work to do, but it seems very promising!
Quoting from 2025.1-Beta1 discussion:
Happy GPU rendering!We stopped the development of headless network rendering based on the existing network rendering architecture a while ago, because these days Octane needs the GPU for a lot more things than just path-tracing and it would make it very hard to manage all the additional data transfers that are required to make that work remotely. We may still continue the development in the future, but it doesn't have priority right now.
However, the OctaneServer is an alternative approach that transfers the source data to another process, which can be remote and thus should allow headless network rendering relatively easily. For now I see this as the more manageable way to implement the concept of headless network rendering.
ciao,
Beppe