About this games platinum

I have soul of cinder left and 2 bosses in the ringed city dlc, and I just found it intriguing to platinum this game and I’ve used all of the earlier boss souls so I can’t even get the rings with their souls, ive missed probably a lot of things but I would like to ask if there were things that I can only do in my first walkthrough without NG rhat if I miss them right now I won’t be able to do them later, I don’t know much about covenants and miracles or anything like that btw.