Send receipts to the carrier and hold out on sending them the title.
Hold out on settling.
Send them listings from different websites that show what the truck is being listed for in similar condition.
May take a few rounds.
Over time they will be pressured to settle and may come up.
I had a Diesel Ford Excursion that was offered $12K. I showed receipts of transmission, turbo and wheel upgrades. Showed listings online. Eventually got $20K.
I had a 2005 Honda Pilot. They offered 2K. I showed receipt for transmission rebuild. Took about 60 days, but they eventually settled for $4K (I wanted $6K).
It’s a dance. Learn it.