Female protagonist

https://www.mangago.me/read-manga/hero_killer_1/
https://www.mangago.me/read-manga/the_fangs_that_pierce_the_heart/
https://www.mangago.me/read-manga/the_returned_c_rank_tank_won_t_die_quantum_scans/
https://www.mangago.me/read-manga/the_daughter_of_the_elemental_king/ (there's a romance tag just because there are a lot of male characters but it ends with no explicit romance)
https://www.mangago.me/read-manga/i_was_trying_to_debut_my_kid_but_i_ended_up_debuting_myself_grim_scans/
https://www.mangago.me/read-manga/the_100_curses_of_illeston_mansion/ (idk who put the romance tag because there's zero romance in the novel)
https://www.mangago.me/read-manga/i_m_quitting_the_hero_s_party/

Oh and you might also like this one https://www.mangago.me/read-manga/camellia/ (the novel has romance with both a woman and a man and a poly ending, BUT the romance is like 10% of the story while the rest is about war and politics)

I want to recc White blood but it has romance. But it's more like a subplot.