As this subforum is for casual play, you're not going to receive much of an answer here. Though I would say through my limited experience in NU that your top picks there are the 3 S-ranks (since Heliolisk is looking likely to rise soon), so Heliolisk, Passimian and Incineroar. All 3 of them have centralised the metagame heavily, Passimian directly and absolutely outclassing a few Pokémon who are still NU by usage, Incineroar chokeholding much of the metagame just because of its typing + Intimidate, and Heliolisk having no counters that are viable outside of countering it, with most teams relying on smart play and fringe checks.
Forums aren't necessarily the best place to get valid answers as far as this topic is concerned. My advice would be to find the discord servers for each tier you still need help with and ask people there.