Sorry, I have no idea what an ambiguous friend means, so I'mma just list out all GLs I know of that have a friends to lovers trope:
Childhood friends to lovers GL:
https://www.mangago.me/read-manga/aoi_hana/
https://www.mangago.me/read-manga/sasameki_koto/
https://www.mangago.me/read-manga/our_yuri_started_with_me_getting_rejected_in_a_dream/
https://www.mangago.me/read-manga/my_angel_childhood_friend_was_a_gal_when_we_met_again/
https://www.mangago.me/read-manga/how_do_i_get_together_with_my_childhood_friend/
https://www.mangago.me/read-manga/kyou_kara_mirai/
https://www.mangago.me/read-manga/relationship_guidelines/
https://www.mangago.me/read-manga/moshi_koi_ga_mieta_nara/
https://www.mangago.me/read-manga/sakura_trick/
https://www.mangago.me/read-manga/mirai_no_fu_fu_desu_kedo/
https://www.mangago.me/read-manga/shouwaru_tensai_osananajimi_to_no_shoubu_ni_makete_hatsutaiken_o_zenbu_ubawareru_hanashi/
https://www.mangago.me/read-manga/the_princess_is_now_the_duke/
https://www.mangago.me/read-manga/tsumetakute_yawaraka/ (cheating)
https://www.mangago.me/read-manga/kono_koi_wa_hoshi_ni_wa_negawanai/ (love triangle - boy and girl love the same girl)
https://www.mangago.me/read-manga/her_lies/ (yandere FL)
https://www.mangago.me/read-manga/jewels_m_k/ (short story)
Best friends to lovers GLs:
https://www.mangago.me/read-manga/hana_ni_arashi_kovachi_luka/
https://www.mangago.me/read-manga/shinyuu_ni_sukina_hito_ga_dekitarashii/
https://www.mangago.me/read-manga/32_cm_height_difference/
https://www.mangago.me/read-manga/onna_tomodachi_to_kekkon_shitemita/
https://www.mangago.me/read-manga/dai_shin_you/
https://www.mangago.me/read-manga/inari_no_kekkon/
https://www.mangago.me/read-manga/kyou_kara_mirai/
https://www.mangago.me/read-manga/ami_chan_s_diary/
https://www.mangago.me/read-manga/mirai_no_fu_fu_desu_kedo/
https://www.mangago.me/read-manga/kiss_it_goodbye/
https://www.mangago.me/read-manga/pan_focus/
https://www.mangago.me/read-manga/relationship_guidelines/
https://www.mangago.me/read-manga/tendering_resignation/
https://www.mangago.me/read-manga/would_you_could_you/
https://www.mangago.me/read-manga/unrequited_love_skill/
https://www.mangago.me/read-manga/45_seconds/
https://www.mangago.me/read-manga/pet_s_aesthetics/
https://www.mangago.me/read-manga/sasameki_koto/
https://www.mangago.me/read-manga/aoi_hana/
https://www.mangago.me/read-manga/girl_friends/
https://www.mangago.me/read-manga/how_do_i_get_together_with_my_childhood_friend/
https://www.mangago.me/read-manga/our_yuri_started_with_me_getting_rejected_in_a_dream/
https://www.mangago.me/read-manga/2dk_g_pen_mezamashi_tokei/
https://www.mangago.me/read-manga/yearning_for_a_night_full_of_you/
https://www.mangago.me/read-manga/dark_mermaid/
https://www.mangago.me/read-manga/shy_na_ano_ko_ni_natsukaretai/
https://www.mangago.me/read-manga/3_bun_matte_mugi_senpai/
https://www.mangago.me/read-manga/tsumetakute_yawaraka/
https://www.mangago.me/read-manga/bai_lijin_among_mortals/ (side couple)
https://www.mangago.me/read-manga/heimin_no_watashi_desu_ga_koushaku_reijou_sama_o_taburakashite_ikiteimasu/
https://www.mangago.me/read-manga/sukeban_to_tenkousei_ga_kudaranai_asobi_o_suru_dake_no_hanashi/
https://www.mangago.me/read-manga/ano_koro_no_aoi_hoshi/
https://www.mangago.me/read-manga/my_angel_childhood_friend_was_a_gal_when_we_met_again/
https://www.mangago.me/read-manga/her_mountain_her_ocean/
https://www.mangago.me/read-manga/the_moon_on_a_rainy_night/
https://www.mangago.me/read-manga/odoriba_ni_sukaato_ga_naru/
https://www.mangago.me/read-manga/only_show_yourself_to_me/
https://www.mangago.me/read-manga/tomoko_mitsuki/
ty
gl/bl where its ambiguous friends to lovers + casual intimacy and banter between the couple