I dunno, it's kinda fun to figure out if there's anything in the morass of shit I've watched that might fit one very narrow set of interests. It's like a puzzle.
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Every person I know that hates anime likes Excel Saga, which is a slapstick nonsense fest from the days of yore. The "every person that I know that hates anime likes Excel Saga" is the primary reason for the recommendation, as it doesn't perfectly check the boxes, see below.
It's about an evil mastermind that is trying to take over a city with the help of a two women who he has do his dirty work, one of whom is endlessly energetic and the other is constantly dying of organ failure and generally not helping as a result.
I'll warn you that there is a side-character that likes little girls, but he's one of the antagonists and his proclivities are not treated as normal, nor does he have a huge role except for creating a robot that looks like a grown woman, and later a younger looking version of this robot; if memory serves, the gag is the pedo gets rejected constantly, iirc in ways that involve fists, by the robot he's actually interested in. It's been a while since I watched it.
The show makes fun of anime in particular, and tropes generally, resulting in the theme shifting basically every episode. It reminds me a tiny bit of Aqua Teen Hunger Force in a lot of ways since the cosmos (looks like a picture of a galaxy cut out in photoshop with arms slapped on it and a female voice, who is in love with the recurring illegal immigrant character that has terrible luck, Pedro) resets the timeline frequently.
Just uh....skip the episode titled "going too far". It's the last one iirc. It's the one where they intentionally do everything that you can't put on TV in the USA.
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Thinking to more recent series, Darker Than Black didn't do much sexualization that I remember, and not of kids in particular, just don't freak out regarding the "dolls" as that name implies things that aren't in evidence when you actually watch the show, but it is a bit anime in a lot of ways, tropes mostly. I liked the original series plenty though, the later ones are a bit odd.
Jormungand was kinda fun action, reminded me of Black Lagoon but with less children (not that Black Lagoon had many children in it, I remember 2 in one of the storylines). IIRC the youngest character is a former child soldier that the show follows but he's not a kid by the time you get to the show. Not as fun as Black Lagoon though.
Ghost in the Shell, the movies specifically, but the Stand Alone Complex series is also excellent and I don't remember any sexualization in any of them that was out of place or in your face. Except maybe the second movie, the catalyst for the plot revolved around sex bots murdering people, but I wouldn't call what you do see particularly "sexual" and most of the movie revolves around other things from a visual perspective.
If you can stand rom-coms, Hyouka is cute and I don't remember much, if any, fan service. It's a bit slice-of-life though so that might be a genre miss.
The Hidamari Sketch shows are VERY slice of life, wholesome, not sexual, just cute, and funny if a bit Japanese. I have been told by a trusted source that the show "gave [him] a headache" so this is a long shot, but it is probably the least sexualized of the slice of life shows in that iirc only an adult teacher that cosplays is sexualized at all. It's not a frequent thing though, usually just long enough for someone to drag her off frame to change. The characters are highschool girls, but again, not sexualized, they just do normal things and funny happens.
Kara No Kyoukai might fit the bill: not super sexualized (iirc there was one antagonist of several that had a sexual element to her rampage), not wacky, looks gorgeous, action is a bit anime though.
I'd normally suggest Sayonara Zetsubou Sensei, but the humor is VERY Japanese, and most of the characters are highschool girls (though the focus is on non-sexual hijinks except for the one character who is herself a joke about fanservice), which probably adds up to a miss for Null even if you can track down the GG subs for the series since they include detailed joke explanation, as some of the jokes are, again, VERY Japanese.
I know Jin-Roh has been rejected but it's one of the few that I think fits the bill completely.
Psycho Pass, at least the first season, is REALLY good dystopian story (which rings a bit close to home these days) and I don't remember it being sexualized at all. Just make sure to get the extended version where the episodes are twice as long, and forget they made any shows after that.
" and the kids are shown peeing? It is assumed that characters are not holding their piss and poo in and just going to the loo off-screen in all other media. Again, this doesn't advance the plot in any way unless you want to argue the little girl had a UTI from exposure, but again, why? Why can't they show she is sick simply by having her cough? No you are a pedo for noticing that this is strange and also pls ignore that Otakus sell shaved ice with pee colored syrup that comes out of a little girls skirt at their conventions.
