This artwork... Look so dmn familiar

Probably because Tojo Sakana made it.

https://www.mangago.me/r/l_search/?name=toujou%20sakana

Same, got similar vibe to these three
Toujou Sakana
Hakase
Sakura Rico/Riko

bro i thought i was going crazy.. i knew this vibe and art from somewhere but nothing is referenced in other author's work section

Do the author have diff pen name? Or is it situation like ogawa chise and her twin?

Google the mangaka's name and baka updates. The list of works is there.

Possibly a collaboration? Or maybe this author took a lot of inspo from them?

I think it is by toujou sakana. I guess the uploader put in the wrong author name. If you go to first page of the manga in chapter 1, you can see tohjo sakana name in the cover. I think ficus js the publisher.