That is exactly my question: do you believe in a Third Temple that will descend from heaven and that the Temple service will return as it was in the First and Second Temples (with some changes here and there, as stated in the sources)?
You cannot ignore such an essential question in light of your approach. I have a feeling that you keep ignoring the implications of your innovation—that one cannot demand belief in factual claims—and that you do not go all the way with this theory, going belief by belief and clarifying whether you accept it. Whereas the common belief is to believe all of the above without examining each belief individually, according to your approach you are supposed to explain each one of them.

I don’t understand what you want. You decided that it will descend from heaven, and now you’re asking whether I believe that? I would guess not. Is that enough?

Do you believe that the Third Temple will be built in a different way and that the Temple service will return to its place? Or do you reject belief in a Third Temple altogether?

There is a difference between not taking something as self-evident and not accepting arguments from authority, on the one hand, and rejecting it out of hand, on the other. There are prophecies about a Third Temple, so it seems likely to me that this will happen (though it is not certain. Prophecies can be interpreted in various ways, and so I also do not see much value in studying them). Beyond that, these things may depend on our decisions and not on prophecies or heavenly actions. If we decide to build it and succeed, then there will be a Temple.