Story where the mc is actually alien or like not from earth, but disguise as human in eart...

I REALLY LIKE THIS ONE
Illusion hunter from another world

Some of these aren’t exactly like what you asked for but feature aliens.

https://www.mangago.zone/read-manga/yome_ga_kore_na_monde/
Disguised as human but is alien ^

https://www.mangago.zone/read-manga/i_became_an_evolving_space_monster/
Becomes a space alien ^

https://www.mangago.zone/read-manga/takopii_no_genzai/
^ protagonist gets help from an alien. Tragedy genre

https://www.mangago.zone/read-manga/big_love_from_ultra_deep_space/
^ big pink alien lady chooses protag as bride

Special mention

https://www.mangago.zone/read-manga/birdy_the_mighty_i/
^guy fuses bodies with space cop

thank you too

nvm i lied, takopi is too sad for my faint heart.

Thats where i got this recommendation idea lmao

yeahhhh

Same here good read though