Bent hangers typically come from turning (torquing) the wheels by backing at sharp angles on concrete or blacktop where the tires grip rather than slide across the surface...
Morryde produces the X-Factor crossmember to reinforce the spring hangers.
https://www.morryde.com/products/x-factor-crossmember/ I found the best price on Amazon a couple years ago when I bought mine, but shop around, you may find better pricing somewhere else. On a trailer, you'll need "one crossmember per spring hanger" (not one per axle) so total for a dual axle trailer is three crossmembers. Expect to spend about $250 for parts.
Using them will "eliminate bent spring hangers, but installing them will transfer that "strong torque force" from the spring hangers to the "next weakest link" in the suspension. On your trailer, that could be the wheels, the tires, the spindle/hub and bearings or it could be the U-bolts that hold the axles to the springs, or, it "could be" any of the suspension components....
While it "could be weak spring hangers on your trailer", I'd suspect that if that were the "only cause" then we'd be hearing about lots of other owners with the same problem since that Lippert frame hanger and suspension system is used on most (if not all) of the heavy fifth wheels produced by Keystone.
I'd look at installing cross braces to prevent future hanger problems, but, as Robert posted above, I'd also try to determine why it happened and eliminate the cause as well as try to prevent it in the future.
ADDED: While you've got the suspension disassembled, this is an EXCELLENT time to install a wet bolt kit with bronze bushing and zerk fittings on the bolts. That way you're less likely to be "riding steel on steel" wearing your bolts, elongating your hanger holes and risking unnecessary wear on your suspension.