Understanding legal language sure is a skill, but this is what I see.
Class A CDL wrote:
Authorizes an individual to drive any combination of vehicles with a GCWR of 26,001 pounds or more if the GVWR of the vehicle(s) towed exceeds 10,000 pounds.
There might be exception for RV trailers somewhere else, but I understand it pretty clearly that you need CDL for trailers >10k
I think it goes even farther than CA law, that require CDL only for trailers, while TX also require it for (10k) toads.
As I said, those things have too many variations, too many interpretations and too many changes done every year
