Just wondering why I never hear anyone or read any article about firestone st tires.
Hard to give a recommendation without knowing what size/load range tires are OEM vs what size/load range your wanting.
Firestone hasn't made a ST (special trailer) tire since the late '70s.
The Firestone Transforce HT makes a excellent trailer tire and has been around for 18- 20 years unlike the Endurance that has a couple of years of service. At 3042 lbs capacity the Firestone Transforse HT have worked great in all those years on trailers with 5.2k and 6k axles.
And 16" LT235/85-16 E commercial grade all steel ply carcass Bridgestone R-238 are just like Michelin XPS Ribs.
LT tires on trailers isn't any thing new. Hell we used LT and P tires before the tire industry gave us the infamous ST tire.
For a trailer that is used a few time here and there like you say the Provider ST or Endurance ST or Carlisle HD ST tire should serve you well unless your trailer has 7k-8k axles. Then a 16" load G all steel ply carcass like the Sailun S637 ST @4080 lbs and 4400 lbs, is tops with haulers and RV trailer owners