Recommend

https://www.mangago.zone/read-manga/hello_green_days/
https://www.mangago.zone/read-manga/come_to_hand/
https://www.mangago.zone/read-manga/tonari_no_metaller_san/

There's some more here of sweet semes who fell in love first: https://www.mangago.zone/home/mangalist/1298011/

https://www.mangago.zone/read-manga/monster_and_ghost/
https://www.mangago.zone/read-manga/loss_time_ni_hanamuke_o/
https://www.mangago.zone/read-manga/hidamari_ga_kikoeru/
https://www.mangago.zone/read-manga/yuutousei_wa_unmei_no_akai_ito_ni_sakaraitai/

The greenest flag ever https://www.mangago.zone/read-manga/reunion/

is he a golden retriever?:
https://www.mangago.zone/home/mangalist/2503878/