Responses
https://www.mangago.zone/read-manga/the_world_s_best_engineer/
Protag past life is a vital part of the plot and a surprising twist in later arc. One of the most well rounded Isekai I've read!

(Preferably with a male mc)
I always watch or read isekai’s where the protagonist never even thinks or acknowledges their past. Understandable if it was a terrible life, but this gets kinda boring after a while. I’m an extremely curious person when it comes to this. Like, if I were isekaied I would definitely think about my past life a bunch.
I kinda wanna read/watch an insekai where maybe the last life plays an important role in the main story. (Doesn’t necessarily have to be important, but maybe frequently mentioned.) Maybe even get to see the protagonists family and acquaintances reactions to their death or disappearance.