...why haven't more eps of that Rena dorama been shared yet? I saw the first ep on YT, but kinda forgot about it...
if you're referring to
Okage sama de, that was just a one episode special drama.
but Rena is appearing on another drama called
Chuugakusei Nikki, again just for one episode.
official site with preview video
HEREits on this Saturday (Nov. 6)