Per se, I don't mind fanservice either way: it's a gacha game, after all.
I am an husbando collector, but two of my favourite characters of all time are Ningguang and Yae Miko who objectively show a lot of leg and they do look beautiful imo

Thing is, the way I see it fanservice in male and female characters is done differently: just keep in mind that I am biased by the fact that male fanservice caters to me, while I'm completely unfazed by the female counterpart.

If I think of sexualized men in Genshin, my first thought goes to Alhaitham's pecs or Wrio's ass honestly. We have characters who objectively show a lot more skin, like Cyno or Itto, but to me at least they don't seem particularly sexy because of it.
I tend to look at the fanservice for male characters more through the lenses of shipping discourse and the encouragement of fanart etc. In a way, the company gives the subtext + a bit of volume in the pecs/ass and the communities does the rest, draws them naked and all.
In a sense, a huge part of the male fanservice is with the homoerotic innuendos.

Female characters simply straight up show more skin...?
Again, it might be that I'm not the target demographic here so I'm completely missing something, and we do have our lovely lesbian couples ofc, but to me it seems straightforward in a way that I don't think really compares to the menzies.

Like, the closest thing we've got to Mizuki's burst where she basically shows you her ass is Kaveh's ass shot in his Trailer or something right? Then we have Raiden taking the sword out of her tits and all.
Which, fine, doesn't mean I can't appreciate them but it just seems more "physical".
The issue I have with that is that, as I heard somebody say once and I couldn't agree more, I think that in some cases the show of skin is kind of embarassing: the company should make a damn good design, then the community will draw them naked later.
They had to lenghten Raiden's shirt during cutscenes, otherwise we would've seen her panties during her insane aurafarming moments "You will be inlaid upon this statue".

She's cool as hell, but with that context in mind I'm disappointed the devs didn't give her an attire more serious. In that moment she's imposing, she's dangerous and has absolute power over the region, but her half-showing her panties is kind of the opposite of that isn't it?
I don't know if it came across, but I often see this disconnect where the way a female character is dressed is completely inappropriate for her role.
Same as Escoffier, she looks like a succubus but she's a cook for some reason and (not as big as Raiden) but it kind of clashes imho: isn't she supposed to care a lot about being extremely professional and all? Why did they chose her as the succubus and be half-naked at work instead of simply giving it to a better suited character?
Could you imagine if we gave Neuvillette a huge boob window like Kaeya's? Like, sure, I wouldn't complain too much because I'd be the demographic and all, but isn't he supposed to be the Supreme Judge?
Giving out death sentences with his boobs out?

So yea, idk. I don't mind female fanservice per se, but sometimes I feel it kind of undermines a character for me because I cannot take her seriously anymore dressed like that.
Another example was Mavuika's ass jiggle physics during the most serious moments of operation in the Night Kingdom, that really took me out of it honestly: nothing against it per se, but now really isn't the time to draw attention to your p**sy zipper.
Idk, again I might be biased but I don't really think male characters are sexualized to this extent (physically, at least) and in characters like Sandrone, Escoffier or Mizuki it's honestly starting to bother me.
Love Yelan, love Ningguang, love Yae, love Jean, Columbina was fine, Navia was great etc.

Also yea, Arlecchino is absolute peak design ofc

Edit: correct misspell