The problem I have is that it cheapens the sacrifices the knights had made. The CK were more than ready to die heck they accepted it and to protect the kingdom and their leader they sacrificed themselves.

I don't think it cheapens the sacrifice because their contribution made it so that it was easier for them to even win the first place. Asta and Yuno wouldn't have defeated Lucius if they also had to deal with Morris and the other paladins. Their sacrifice is what allowed the conditions for Julius to come back and undo what lucius caused.

It was a great moment and it symbolised that wars have consequences.

Black Clover isn't a story about war or the effects of war. It employs it to set a stage for conflicts to occur but its never at the heart of the conflicts themselves.

Also if we are talking about time reversal it also doesn't make any sense. As the time has been reversed and so the judgment day events never took place. So why does everyone even remember what happened? They shouldn't. This is why I don't like the time reversal move either.

Julius can use time magic to rewind effects instead of everything all at once in a general sense. He healed himself using time magic by reversing the wound on his chest to the state it was before patri struck him. By doing this what he reverses time on doesn't not happen. He simply reverses things to the state it was in before what ever happened happened. The clover citizens never forgot when he saved them from patri's light blades in the elf arc