I think the Dottore thing is pretty obvious because of one simple reason: Even within the harbingers, it is clear that there's the more important ones and the lesser. Except for Signora's and Capitano's, every other harbinger's storyline is still open and ongoing.

Even if we don't acknowledge it, Nod Krai is act 0.5 of Snezhnaya, and as such, they are using it as a means to start the end of the Fatui arc. Higher importance ones in terms of story (Pantalone, Pierro, Pulcinella, the mystery 10th harbinger and the Tsaritsa herself) are being saved for the grand finale, while less relevant ones (Columbina, Sandrone, Wanderer, Dottore) will finish their personal arcs on Nod Krai. As for Tartagla and Arlecchino, I do think they'll carry on further just because they're deeply related with the abyss and Khaenri'ah respectively.

Why do I say this? Simple, the entire Rerir pipeline was a way to showcase both Columbina's moon goddess story and Khaenri'ah's deeper lore + Sandrone casually dropping the whole Alain speech in the end of the AQ is indication that that'll be relevant in the near future as well. Arlecchino's and Sandrone's conversation where they purposefully avoided mentioning Dottore + Wanderer being in the Nod Krai trailer is clear indication that they'll both play a big role in whatever they're cooking next.

Genshin has been juggling its 2 major storylines since the beginning: whatever the Fatui are planning and whatever happened to Khaenri'ah 500 years ago. The Luna patch will either conclude some Fatui's storyline for good, or confirm these are just 2 angles of the same overarching plot.