Wow, sorry to read this. Those pics tell it all. I'm no RV expert, but can say I got an almost 15 year old camper that presents better than that and 10-20 year old cargo trailers that have 10-20x the miles on them than yours that pull straight.
You've done your diligence trying to get resolution nicely and you're getting the runaround. Lawyers mean $ but you'll be out less $ to get the right lawyer to send the right demand to the dealer and mfg.
I wouldn't settle for less than full refund including tax etc to date. And shoot for damages, loss of use, legal fees, time spent etc. Then they can negotiate down to just giving you your money back and hopefully legal fees.
Bad situation for sure. seems you're dealing with shoddy/dangerous workmanship and then either major structural defect or a damaged unit that was sold as new. Hate lawyers but one will have a field day here!