Like the title says. I want to read something that's fluffy and cute but also a bit offbeat and whimsical. Like... touches of magic? Or, I guess I don't mind stuff that's quirky in a normal way.

Romance would be lovely, but only if it doesn't make me want to tear my hair out i.e. no love triangles pls. Also I'd like if it had a slice-of-life-ish vibe? Nothing too plotty, I guess.

Some examples:
Koudaike no Hitobito
Itsuya-san
Akai Michi
I Am Currently Living with a Bear
Ran to Haiiro no Sekai

Please check my lists before recommending! Thank uuuuuu.

Check this one out

Stella to Mille Feuille

Ooh, I love these types of manga too. So, uh, here are a bunch of recommendations.

Acony
Chijou wa Pocket no Naka no Niwa
Dainana Joshikai Houkou
Flying Witch
Gendai Majo Zukan
Hakumei to Mikochi
Hibiki no Mahou
Himitsu no Kaidan
Hitsugi Katsugi no Kuro. - Kaichu Tabi no Wa
Houseki no Kuni
Kumamiko
Kyou, Curry!
Kyoukai Senjou no Rinbo
Majo to Neko no Hanashi
Mill
Natsukashi Machi no Rozione
Nickelodeon
Nina-san no Mahou Seikatsu
Ryuu no Kawaii Nanatsu no Ko
Socks Goblin
Somali to Mori no Kami-sama
Sumikko no Sora-san

Plotty but fun...
Dungeon Meshi
Majo no Shinzou

Most of these don't have romance, unfortunately.

Hmm... Issho ni Neyou yo ?

Yep, quirky-cute manga are amazing. And whimsical slice-of-life is something manga does better than any other type of fiction, imo.

Iwaoka Hisae's works. Practically all of them fit.
Noramimi
Hinamatsuri
Flat (AOGIRI Natsu)
Doubutsu no Oishasan
Kuro (Somato)
Mokke
Neko Musume Michikusa Nikki
Ryushika Ryushika
Sketchbook
Kokoro ni Hana wo!!
Totsukuni no Shoujo
It's My Life
Youkai Apato no Yuuga na Nichijou
Vampire Doll
Bernie no Enitsuki
One Fine Day (Sirial)
Milkyway Hitchhiking
Dusk Story - Tasogare Monogatari
Cowa!
Little Little
Jauhara Genya
Sumire 16-sai!! and Sumire 17-sai!!
Shinkuu Yuusetsu
Family Complex
Papi Nyang
Binbou Shimai Monogatari
Pikupiku Sentarou Selection
K-ON!
Chi's Sweet Home
Boku Wa Ne
Gakkou no Sensei
Neko Mix Genkitan Toraji
Mizuiro Ether
Tsubaki Biyori
Aoi Uroko to Suna no Machi
Hatarake, Kentauros!
Neko no Machi no Ko
Sakai no Musume - Cat in the Car
Wild Life
Tom Sawyer
Daga ga Tame ni Hagane wa Naru
Futatsu no Spica
Chichikogusa
Orenchi no Furo Jijou
Oushitsu Kyoushi Haine
Aka-chan to Boku
Kominami Shoutarou, Ie o Deru o Hjimemashita.
Tenshi no Shinzou

Not many of these have romance, I'm afraid.

(I only looked through your reading and complete lists, btw. Sorry, didn't have time to check the others.)

Maybe give some of these a try.

Matsuru Kami
Katana
Harlem Beat wa Yoake Made
Twink Twink
Tamashii no Futago
Moon Trick
Oz no Kakashi Tsukai
Kirikagohime to Mahoutsukai
HaruHana
LLLL
Magi no Okurimono
Hai ni Naru Made (the first story and its short epilogue at the end of the fifth chapter)
Shokugyou Tenshi
Maimiko Touko no Jikenbo
Halloween Town - Party Time
Mein Ritter - Watashi no Kishi
Chikutaku Bonbon
Yokohama Kaidashi Kikou