Have you read the BEST new-gen DARK FANTASY, ACTION SHOUNEN MANGA of the 2020s, the peak of human literature, Kagurabachi? If you're looking for a story with a more slow-burning pacing and world-building, but masterfully-written plot, realistically written and interesting characters with great designs, GORGEOUS ART that evolves with each new chapter, MOVIE-LIKE fighting choreography, BEAUTIFUL panelling and composition and NO ROMANCE, ZERO FANSERVICE AND ABSOLUTELY NO SEXUALISATION, ESPECIALLY OF IT'S FEMALE CAST!! OH ALSO IMPORTANT MENTION; DON'T DROP THIS AT CHAPTER 58 (IYKYK), TRUST THE PROCESS OF HOKAZONO-SENSEI'S GENIUS!! GO READ IT NOW!!!
https://www.mangago.me/read-manga/kagurabachi/ (PEAK FICTION)
And these too:
https://www.mangago.me/read-manga/dear_flowers_that_bloom_in_days_of_yore/ (GL)
https://www.mangago.me/read-manga/nippon_sangoku_the_three_nations_of_the_crimson_sun/ (shounen)
https://www.mangago.me/read-manga/doushi_shoujo_yo_teki_wo_ute/ (shounen)
the hunter wants to live quietly
beauty and the west chamber
stories with deep, complex and interesting character dynamics. bl, gl, hetero or no romance, any is fine