But all the 'experts' say there is only Tesla Brand DCFC in the world.
There is no DCFC at all at any speed for non-Teslas according to The InterWebbyExperts.
I simply don't think that is accurate.
You can say Tesla has more stalls, or a wider spread, or faster charging, but you shouldn't say Tesla is the only DCFC solution.
The comedy is, that if you did go from LA to SD, and you wanted to charge while at a meeting, you'd probably use CSS or CHAdeMO since there is no Supercharger in SD AFAIK. Tesla's operational radius is assisted by a secondary and tertiary grid that "doesn't even exist at all".