Prayer

That is, are the main things, which are the recitation of the Shema and its blessings and the Amidah, sufficient? Or did I not understand the Rabbi's intention?

Indeed, on a principled level, it is possible (with the blessings of dawn, blessed is he who said and praised). I thought the question was a principled one.
If you intend to apply it in practice, there are a few reservations:
1. When praying in a minyan, it is more complicated.
2. The question is what is the need for it (how difficult is it for you to pray as usual). There is value in keeping a custom, and therefore its abolition requires necessity.

The need is for feeling. God does not intervene and does not answer prayers (according to the Rabbi), so prayer becomes unnecessary. Or we simply pray because we have to say these words, and this is how it was determined during the Great Knesset, so feeling does not change anything and we must stick to the formula.

There is a misunderstanding here. The purpose of most prayers is not requests. It is a small minority of them. If this is the need, there is no justification for changing (since the requests part is part of the standing that we do not have the authority to change. And as for intentions, one can make intentions for those in need, for whom God may intervene and help them. In rare cases, this may happen).
I will elaborate more on this matter in my book (The Trilogy).

Is there any expectation for the trilogy to be released? Looking forward to it 🙂