I think it makes sense to have those concerns (the other main one that people seem to have prior to reading the series is its handling of gender). What I would say, going in, is that within the world of the series, most people think that their way of doing religion, gender, and land relations is the best, the most enlightened, the most utopian, and the only way to avoid the wars, inequalities, and injustices of the past — but Palmer herself, and the characters within the series as it progresses, become aware of the flaws in their own thinking, and indeed of the arrogance of their unexamined assumptions around these issues. I also feel very strongly that Palmer herself shows signs in the series' concluding chapters of actually recognising that she, the author, got things wrong (due to not thinking things through completely, due to incomplete information, and so on) and that she has rethought some of the series' initial assumptions. I have no exact proof that this is what's happened, but that's what I feel is going on, reading between the lines. I don't know how much that reassures you.

(My feeling regarding religion in the series is that most characters — and indeed the author in the early books — defaulted to proselytising religions when thinking about religion, and all handling of religion both within text and without flows from that incorrect default. As to the land relations, I find it hard to think objectively about this because as an immigrant with three nationalities — one of which was imposed on me by an accident of birth and which I basically can't get rid of, even though I want to, one of which I chose had its most attractive aspects taken away by my new fellow citizens literally on the same day I received the citizenship — who had to do a lot of expensive paperwork to continue living in the place where I want to live, the idea of an identity which is based on a conscious choice to align to others who share one's values seems like such a paradise that I would endure anything to exist in such a world!)

I feel that the Terra Ignota books are going to be something that you argue with, but find intellectually interesting to argue with, if you see what I mean. I'm not sure your concerns will be allayed, and I never encourage people to persist with books (or other works of media) they find distasteful, given it's meant to be reading for pleasure, but I think there will be enough there for you to know after the first book if it's worth continuing.