Fed up with tire blow outs!!!

All 3 tires did not blow at the same time. The first to go was the driver side rear. This weekend the passenger side rear blew on my way to the campground. On my way home the passenger side front went. Each time I heard the tire pop I pulled over immediately.

Same scenario from others/myself who had multiple "blowouts" using low cost ST tires like the blowmax or just old tires.
When one blows out or a tread delam with loss of air usually the others will come pretty quick some where down the road.
On a multi axle trailer like yours, with equalizer bars, having a flat on one tire will not overload the next one in line. The flat tire is still carrying weight through the equalizer bar. If the flat is ran long enough the tire is quickly worn away down to the rim and its started to grind away. Steel wheels make a beautiful spark shower at nite.

What usually goes down is the good tire next to the one that is shredding get cut/bruised from steel belts as the sling about at 60 mph. Some where down the road it may give you grief.

If the 14" Endurance are on back order I would go with the Providers from Taskmaster or the Carlisle HD I mentioned in a reply above. Just like the Endurance both are the new gen higher speed rated ST tires.

I've pulled work trailers over a million miles. Through trial and error I've learned trailers can be over tired. Always went back to choosing a tire with 10-15 percent capacity above the trailers OEM axle ratings.
Many folks like to go with a good brand E tire when replacing cheap OEM C tires then claim the E was superior. A better quality OEM C tire does the same thing.

Don't get hung up on the thinking a D or E tire is needed..... a better quality OEM C tire will work just fine if they have plenty of capacity.