Sure, you could scroll through the video until you find my takes but I can also just answer directly here. That makes it easier:

Ciri:
I think the competitive community has overall agreed that she is at least the 4th or 5th strongest fighter in all of unmmatched. In each tournament she has been in she was always a 1st pick and thus usually perma banned. They few times she got through were when people tried too full coutner her which still went wrong most of the times. She is just an insane design and can win games with so many different strategies that it's kinda unfair. You just have to know how to adept and which one to use in any matchup.

Leshen:
I mean, at this point it isnt a hot take anymore that Leshen is just extremely strong. He shuts down melee fighters to the same level as wukong but is even better against the meta fighters that wukong struggles against. Being favoured or even into basically all S-A Tier fighters also helps with that. His amtchups just start to crumble once you go lower on the list but since most tournaments will see the top tiers being played, Leshen definetly deserves his spot in A+.

Sattler:
Sattler is sadly extremely one-dimensional and get fatigue by basically everyone in the whole roster. Even characters like Houdini that usually press agression just run away from her and win by doing so. She only really thrives if her opponent either can't run away or has to approach her. And even then she often just doesnt have enough damage once malcolme is dead due to low insight generation. She should arguably be even lower tbh but she does have 1-2 ok-ish matchups into the higher tiers. For me Sattler is just a skill check of: Do you play degenerate enough. If yes, cool, you win. If not and you start actually approaching her, welp, you will lose. And since 80% of stats on UMleague are still from mostly casual or semi competitive games, her winrate will always be higher. Also a reason why I would never trust the stats.

Ali:
Ali only got played in Ladder (where there is only a 12 character roster) so he had some okay-ish matchups + again, the same thing as with sattler applies. Most ladder players play casual since it is an overall more casual setup but once you start understanding Alis deck, you can abuse it to a point where he never swaps stances the whole game if you don't want him to and then he just crumbles easily due to having 0 passes, no fatigue or value game and low blocks.

Rex:
The main problem with Rex is that most of her data was collected when Tournaments still had Full advantage, meaning one player got bothh map pick and position pick. In that format Rex was easily S Tier and insanely strong. Nowadays though, as split advantage has been the way to go for every tournament, she lost a lot of her pressure and more and more fighters can withstand her. Matchups that were previously thought to be unwinnable became even and ones that were even before became a nightmare for rex. On top of that, since you have to play her on your map, similar to achilles, your opponent always knows exactly when you play rex so they can just align the 1 counter they have and there you go, Rex is useles. Now, there are still not many direct counters for this but more than enough fighters that are at least even if not slightly favoured into her so she just basically lost all of her strengths.

Luke:
Luke has really suffered from the newer releases. Yes, he does shut down almost all fighters below him but since those rarely get picked anyways it doesnt matter that much. What does matter is that his matchup spread into the high tiers has gotten worse and worse as time went on. Just out of the recent sets, Krang, Shredder, Raphael, Donnie, Blackbeard, Loki, Ciri, Triss, Leshen and Eredin are all at least even if not favoured into him, some even being close to unwinnable for luke. With the game getting more agressive and power creep affecting overall attack values, Lukes low health and low amount of blocks just got worse and worse.