I get the whole quest thing but this is the same in every game maker, its HOW you make quests through eventing, its always been this way. Once you've done it a few times though it becomes simple to replicate and much quicker, it just takes time to get comfortable with it.
However, I agree though that the developers should add some type of quest system built into Bakin, kinda like how they've done the monster book.. BUT they no doubt won't do it. The quest book should have sections to add stages of the quest in for updates as you progress the quest, picture capability, etc. The fact this STILL don't exist in Bakin is criminal for an RPG making engine.
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The whole language thing, you can program your game in your language already but the editor remains English unfortunately, which i'm guessing is what youre talking about.. the bakin engine itself you want translated. I understand why they haven't done this yet, as it costs to employ someone to translate an entire engine/game/etc. If the German community for Bakin got together and offered to translate it themselves for SmielBOOM then they might take that into account and that might be acceptable to them. It's worth a try to ask.

https://thatdaledude.itch.io/quest-system

Just in case, this plugin may help you!

And Chinese, thank you.