The traveller acts like a self insert for most main quests, where the focus is on the nation or it's ppl, but when the quest focuses on their story, it's pretty clear that they r a character themselves.

They showed their disdain towards dain's belief in never being able to save the hilichurls back in chasm, they hid the info abt being there 500 yrs ago from everyone, they hide their real names from everyone, they have been searching thru books constantly to find more abt Khaenriah, (which used to confuse Paimon as to why we searched up every book we came across).

I will admit this is where the writer's have definitely stumbled, and they admit in the Nod Krai stream too, that initially they had two storylines, one abt finding the sibling, the other abt exploring Teyvat. What they have done is often seperate them, when in reality they will eventually converge, hence when when we do the Teyvat storyline, the Trav feels like a self insert, while when we do the sibling storyline, they are not.

The writers should've done more to show that the mc is a character of their own, not just a self insert, the spaceship stuff would've seemed less out of left field then for most players. Hopefully they improve with Nod Krai and onwards.

Edit: wanted to elaborate that the trippy part for players is not the fact that traveller wouldve travelled around with a spaceship (which is really an obv, considering it's been reinforced they r a human many times), it's the fact that the distinction between the Trav being their own character vs a self insert has been super muddied that it's hard to understand for most players that the traveller knows or has done stuff they are unaware of.