Since I'm not the kind of person who plays games that I have played again, I'm now looking for some good long-term examples for the 3DS.
By that I mean something like Animal Crossing, which could actually be played forever. So it doesn't have to be the same genre but something that I can't play through in a week.
Among other things, I'm also looking for good role-playing games for DS or Wii (normal).
Try Monster Hunter
Actually almost all RPG's such as:
Xenoblade, Pokemon parts, Monster Hunter parts, Fire Emblen parts, Zelda… There are quite a few
Then I could also recommend Shin Megami Tensei IV & Dragon Quest which used to be one of my favorite games on 3DS ^^
Harvest Moon and Story of Seasons.
Xenoblade Chronicles
For 3DS, Monster Hunter Stories, a turn-based role-playing game is completely in German with an open world.
I got it through but actually not after the end credits you can keep playing because there are enough open quests
Also for 3DS, Lego Undercover is a game similar to GTA with a fairly open world, there are still a lot of open things to do after the end credits