So in 16 years I have bent two axles. (Both times my fault). Sourced both axles from Croft Trailer in Kansas City. Second time I was in Florida and the repair shop was quoted three weeks for the new axle. Croft trailer built and shipped the new axle to Florida in 4 days. (Stock Dexter axle but had to be shortened to fit my rig). Many of my RV friends in KC use them, as well as several MOC members. Might give them a try.
https://www.crofttrailer.com/
Full disclosure I have been associated personally and professionally with family members of this company for many years.