Corning now sells optical Thunderbolt 3 cables.
https://www.corning.com/optical-cables-by-corning/worldwide/en/products/thunderbolt-optical-cables.html
https://www.bhphotovideo.com/c/products/Thunderbolt-Cables-Adapters/ci/17952/N/4042754092?filters=fct_a_thunderbolt-version_5764%3Athunderbolt-3%2Cfct_brand_name%3Aoptical-cables-by-corning
Maybe we could revisit Linus' server room thunderbolt solution? Last I know of, he used some secret sauce cable in this video: