yetey1 I've been in the industry for a little over 3 years now and in my opinion the best tube steel manufacturer is American Steel Carports, Inc. They are not the biggest, but they are either #2 or #3 (under Carolina Carports and Eagle Carports).
My problem with Eagle and Carolina and really all the other manufacturers based in Mount Airy or Dobson, NC is: their customer service sucks, lead times are extremely long, and they usually don't care about fixing issues in a timely matter if something goes wrong during installation. In my opinion the only advantage to them is price.
If you share your location I can let you know if I'm aware of any other manufacturers that cover the area and are reputable, but yeah, my dealership uses American Steel Carports for every customer we possibly can. It costs me a lot of sales, but I have a five star rating on Google/TrustPilot; my customers are happy, and I'm doing well enough to survive, so I don't really care that much.