Ultra Ethernet is competing with InfiniBand (the more flexible more scalable but slower mostly CPU-centric fabric technically developed by an industry consortium but in practice single sourced from NVIDIA) and, to a lesser extent, OmniPath (formerly Intel). Though many of the non-IB fabrics still rely on nVidia silicon at least for the HBA part.
https://www.phoronix.com/news/Ultra-Ethernet-Consortium