350 kW chargers are already rolling out on the Ionity, Fastned, and Electrify America networks. They use the CCS standard. They already work with cars on the road:
https://insideevs.com/first-ionity-350-kw-chargers-denmark/
https://fastned.nl/nl/blog/post/everything-you-ve-always-wan...
https://insideevs.com/here-are-the-350-kw-nad-150-kw-abb-cha...
Why is Tesla so far behind?