It's like a "desert that lovely a sweet" vs a "desert that's sweet, but also bitter". You can like both. And the author is a person who made the latter, but evinces a jealousy of the former. And volume four in some ways is sweeter than volume 1. But... volume 4 has a pretty big bitter side to it if you think about it. Volume three also has a quite bitter side to it, though it also is underplayed.
So when the author says that she's jealous of the sweetness of the manga version of volume 1, I think that's true. But when she keeps including bitterness in the stories, I have to conclude that that jealousy does not extend far enough to change her approach that much.
The manga & anime both make a major change from the LN. Some people quite like that, but many fans of the LN are not happy with that. Clearly the change has resulted in a lot of pushback from the fans, which has had to be addressed by the author. And while the author has approved of the alternate takes, a reader has to suspect that this is an attempt to save face, and calm down the controversy.
Saying "I'm jealous of the way that you did that." is not the same as saying "I wish I did it that way." There's an intentional vagueness there characteristic of a diplomatic statement.
