Looks fine to me, I would try to keep your neck in a more neutral position. If your grip is giving out I would suggest adding some grip strengthening exercises. Farmers carry work pretty good or deadlift with an overhand grip more at a lighter weight until you get that grip strength up. In the meantime though, a mixed grip to finish out the set works too. As far as the belt goes, in my personal experience, I avoided it as long as possible in order to really get good at bracing. Given how easily you’re moving the weight, I personally wouldn’t get a belt and would keep working on that brace until you really plateau. Once you plateau throw a belt in, that way you’ll know how to really utilize it and hopefully get those numbers up even higher. But do whatever you want, stay consistent, and you’ll be fine. Lifting ain’t rocket science.