Also, something about NL: he really isn't helped by always having been able to utterly dominate any possible rivals when it comes to basically everything. This means that while he sees that Su Luo could actually be somewhat his equal, he takes a while to actually internalize it. It's a very logical mistake for him to make, and he IS shown as being surprised again and again when he under-estimate Su Luo.
When he stops doing so he gets a lot more bearable.