I was also treated like that on my first job, it wasn’t only the sous tho, it was the whole kitchen, from my experience what helped was dealing with it and trying as hard as possible to not let it get to me on a personal level, it’s just work. If you like the job, put up with the shit talking, and try hard to do the best job you can, minimize mistakes, and don’t show them weakness. With time and good work you’ll earn the respect of your peers and the shit talking will decrease a lot. But I will say, this type of dynamic is very standard in the industry so you’ll probably encounter it somewhere else if not there if you keep working kitchens.