The suspension on my 2015 Nash 22H needed to be completely replaced. The equalizers were cracked, the shackle bolt holes were oval, the spring bushings were worn out, the bolts showed wear patterns...
"Off-road" that is pure bull dung. Even the North American camping trailers are too dainty. We have a OutdoorRV with a Northwood frame under it. Ours is used on gravel, we had a bent 3500# axel but no serious wear,when I replaced the axels with 5200# and added wet bolts. We had more and rougher mileage on ours when I redid it.
My utility trailer is poster child for suspension wear.