I find this an interesting conversation you are all having
The main being is this going to have NTR or not?
Firstly, would it be NTR if you are talking about Alexa, who is artificial intelligence (robot)?
Secondly, I have seen many games that have declared tags for NTR which have not quite understood the meaning of NTR, it can be due to the death of a character, not just betrayal and sex. so... if that was something planned then would be giving some of the story away already, spoilers you could say.
Finally, the dev has said he is not going to say at this point, so if it's such a deal-breaker for you to know now, then maybe it's best you don't play the game and move on and find something else to play?
From what I have seen so far it is not the same as other games and stories, not the usual incest/family thing, so not sure trying to define it by tags is really required... which is also why the next thing to be brought up will be Incest patching no doubt... Yes, spoiler alert...
Alexa is your mother