First, TYBW AP. Based on the translation of the video, I disagree with the idea that Giselle doesn't have the combat capability of a Captain. Unless raws says something different, to me, she is talking about her actual ability not being something that works in a similar manner to the Power and the Glutton, that being killing with the power. And we do see her tactic is to control them, then kill as opposed to just kill. Still, that is just my interpretation, so it's understandable if that doesn't make sense. Second, she was stated to have better combat capabilities while using Blut to fight compared to alive Bambi in Klub Outside (currently on her profile). This would mean Bambi is weaker than a Captain, which contradict the anime and manga with her fight against Sajin in the first invasion. Third, and perhaps most important, this is a quote from Giselle after she lost a decent chunk of power from Yhwach's vacuum. I see no reason why this has to be applied to her TYBW key, especially since we have no idea how much weaker she got. Fourth, and maybe this doesn't matter, but I don't see how her ability to not turn someone because they have Captain level power means she's weaker, as it could be a limitation of her ability like how she can't use it on Quincies. Maybe her ability requires the opponent to be weakened first? This last point is more guesswork than substantial proof though, so you can ignore it. But we do have examples in universe such as Kido that is hard to break from one side but extremely easy from another, but again, speculation.
Second, LS. I have no opinions on anything involving LS and Speed rn, so whatever
Third, CFYOW Giselle. These keys are terrible rn, but for that matter, I could easily see CFYOW Giselle having an Unknown rating due to her power loss.