I used it a long time ago like as a solo-ish run for SOMETHiNG in FRLG, forget what it was that I was doing, but Jynx was busted
even without Calm Mind. The only reason I didn't quote my experience with it just now was because it's been literal years since that happened and thus requires taking it with the whole salt shaker. It gained levels like crazy.
It's a shame Jynx never really is great in any of the other games though. It's tailor made for the back half of Kanto.
Okay, so about Hitmonlee. It's really attractive
on paper. 120 Attack with 87 Speed
sounds like it'd be an easy B-tier. But I think it's way more at home in C.
Here were my experiences with Hitmonlee and Hitmonchan, The short version of that post (I for all intents and purposes consider Lee and Chan roughly the same Pokemon) was that I felt they chugged boosts way too much to be viable, like glancing back at my old thoughts the only one I didn't seem to need boosts to kill the relevant things was like...Giovanni...who is lol Giovanni, not exactly a big point in their favor - you really, really have to have a bad team to not faceroll over Giovanni with something in a standard party. This isn't a comment on Hitmons, I am aware, but I weigh Giovanni less than other bosses.
But back to Bulk Up boosts. The more you boost in major battles, the more you open yourself up to recieving trolling critical hits (see: Slowbro). On top of this, Fighting has never,
ever been a good type in Kanto, regardless of how great your stats are. Erika resists Fighting, Koga resists it, Sabrina resists it, Blaine might as well resist it with double Intimidate. On top of this, Agatha makes Fighting types borderline useless outside MAYBE one KO, and Lance really isn't much better - Hyper Beam is just going to nuke you AND Gyarados has Intimidate.
Boosting means matchups inherently take longer than say, a Pokemon that just spams Surf, Flamethrower, or what have you (which are resisted way less). If you're a Fighting type in these games, it is a huge, HUGE uphill battle to make B tier any way you slice it unless you have like, legendary stats or something like Lugia in HGSS where you faceroll everything at the League. Hitmons and Machamp don't really have that luxury, though I can't speak for Machamp entirely as I haven't used it.
So you've got a Pokemon that, while it can sweep Sabrina through Ai idiocy, more or less doesn't start being relevant unless it takes a turn or two to boost, upon which most of the time, you won't even use Fighting moves. You play like a STAB-less Normal type, and there are plenty of Normal types who Strength / Return better obviously. Yes, we tier Pokemon on their own merits, but spamming Brick Break almost exclusively with Hitmons won't get you anywhere, you HAVE to use Strength / Return constantly.
Hitmonchan and Hitmonlee, despite how attractive the stats are, are just Pokemon you have to use in super specific ways that don't even highlight their strengths as Fighting types - the Fighting type brings almost nothing but negatives for them because their STAB is always resisted.
Hope this response helps!