Want omegaverse?
Yeah it will work weither it's bl or straight, manhwa or manga however I don't like manhua.
There is hidden baby
https://www.mangago.zone/read-manga/kiss_me_if_you_can/
https://www.mangago.zone/read-manga/stigma_2/
https://www.mangago.zone/read-manga/again_signal_acel/
https://www.mangago.zone/read-manga/ex_husband_wants_to_marry_again/
https://www.mangago.zone/read-manga/percentage_of_love/
https://www.mangago.zone/read-manga/hyacinth/
https://www.mangago.zone/read-manga/struggle_1/
https://www.mangago.zone/read-manga/dear_benjamin/
https://www.mangago.zone/read-manga/it_s_my_baby/
https://www.mangago.zone/read-manga/alpha_no_ie_no_ko/
https://www.mangago.zone/read-manga/arima_wants_to_be_an_omega/
https://www.mangago.zone/read-manga/kimi_to_tsugai_ni_narenai_riyuu/
https://www.mangago.zone/read-manga/wakeari_omega_wa_nige_no_itte/
https://www.mangago.zone/read-manga/macguffin/
Promo? Looks good
https://www.mangago.zone/read-manga/the_villain_who_became_pregnant_with_the_alpha_s_child/
And there are babies, but not really hidden and not really of ml/mc
https://www.mangago.zone/read-manga/the_yandere_top_fatger_is_being_teased/
https://www.mangago.zone/read-manga/kozure_omega_to_boukun_yakuza/
There you have list of omegaverse with "hidden" kiddos
Is there any manhwa or mangas with child who looks like me...types of plot..like hiding secret child.