When I bought my trailer, it had one wheel well and some interior bits shredded. I rebuilt it using 404 steel, the same stuff that is in tanks and garbage trucks. The other plastic wheel well was reinforced with steel strap so, in the event of a blowout, it may buy me some time. I also applied fiberglass to the underside of the plastic, same thoughts in mind. Both wheel wells are framed, inside, with 2 x 4's and plywood.
Probably the best thing to do is to avoid blowouts, initially. Continual inspection and checking air pressure, replacement at short intervals, and buying tires that give some headroom for the weight carried.
And then there is TPMS.