I feel like a lot of you aren't familiar with Korean longstrip comics or something. Seven chapters in, it's legitimately no surprise the isekai element hasn't been thoroughly explored. I swear, these things tend to move slower than molasses attempting to ooze uphill. It wouldn't even be strange if the entire first "season" (if it even gets split into seasons, not all of them do) did nothing of interest with that tidbit.
Also, a while back someone mentioned Chekhov's gun, but Chekhov's gun didn't really offer much of a specific time limit between the introduction of something and its use (Wikipedia has three different versions of quotes for Chekhov's gun, two of which give an illusion of an acceptable time frame but it's not like that was actually the focus in either of them). It's just that if something is brought up it should be important enough to have ever brought any attention to it at all. They could wait until the series finale to do anything with her past life memories and it'd still be fine, other than annoying all of you along the way up to that point because it took so long to bring it up properly.