Regarding the architect's fee: That is probably roughly the HOAI fee, I assume. Yes, that is really a lot for my taste. But I'm afraid that in metropolitan areas it won't be any different if you want to build with an architect and individual contracts. Whether it is worth it to you is something you have to decide for yourself. Whether in such a case going to a general contractor (GU) might be better... Just go to construction companies, see what they have to offer, get a quote. And then you'll see if you are better off that way. If not, I would prefer the architect over the GU, but that's my personal preference.
We ourselves paid our architect about 20 percent of your offer from start to finish, that is from the design to the completed construction management. Here in the region, no one pays according to HOAI and 90 percent build with an architect and individual contracts (that's the usual way here, since GUs are usually more expensive - as I said, the clocks still tick a bit differently here). For us, our architect was worth every cent. But almost 60k is of course quite a different figure. However, our construction moved financially in a completely different dimension anyway.
Well, we are also about the same regarding the fee. That is of course a lot of money, but when I think that my architect manages a project for about 2 years and would only demand 20% of what the OP mentioned, I wouldn't believe that he really takes care of it. If I were to manage a project for 2 years and get 10,000–20,000 € for it, I would also politely decline.
Yes, the fee is based on the HOAI. All architects here do it that way. I do find that it is a lot of money, but a real alternative (except for the GU that everyone talks about, which I don't find...) . I wonder if I should negotiate again...
Are the land costs included in your house construction costs of €655,000 or are those just the building costs?