I actually follow a YouTube channel called Akira, she reads the novel and delivers to us latest events, also people discuss in the comments that the author Natsu originally wanted to end it in v12 as open-ending with a kiss. However, she scrapped this idea to them develop more in character and story, still that doesn't mean she will not let it end as open-ending. Anyways here are the links if you would like:
https://youtu.be/nH3TlSzQ7dQ
https://screenrant.com/the-apothecary-diaries-original-ending-plans-manga-light-novel/#:~:text=By%20not%20ending%20the%20story,Source:%20@keiuzuki/X
And this is exactly what she said:
"Ultimately, I want to end the story in a way that satisfies the readers and leaves them with a lingering impression.
Rather than concluding with [happily ever after], I want to show that even though the story has ended, their lives still continue.
I don't know when that will be, but I hope to be able to end it in that way."
Let's hope we get a proper ending ╮( ̄▽ ̄)╭

I just saw somewhere that the ending will be open-ended. Why are Japanese writers so obsessed with open endings? I'm so tired of reading stories for years, only to end up with an open ending.
I really hope we get a proper ending for this one at least.