Can someone inform me the highest level mon each gym leader/E4 member/champion has?

I’m doing a nuzlocke surprise playthrough and don’t want to spoil the game myself. First time playing to be more specific. I’m doing level limits so I don’t over/underlevel (the game is much more fun for me that way). I’m not checking on sites because I don’t want to accidentally reveal one of their pokemon. If someone could check on YouTube, or some site, and basically do the dirty work for me, that would be awesome.

And please don’t say things like “Kind of ruins the surprise if you know exactly what level to grind to and win all the battles easily.” It’s a personal, customized challenge I’m creating for myself that would be the most fun for me. After all, it’s been said that it’s the experience that counts, right?

Play on hard mode, there is a level limit.

if i don’t remember wrong at wiki you can find this info

Gyms 7-8 & Elite 4 are not in the game yet, but will be as of the next patch.