Custom as a formal obligation

In principle, all of these are obligatory, although the boundaries of customs are not clear-cut, and each person has their own Torah. As for your question about a custom without a soul, I see no difference between this and any law that is observed without its soul. What is the difference between absolution without intention and prayer without intention? Furthermore, I disagree with you that the desire to rush necessarily indicates a lack of intention. And beyond that, there are also more general intentions that are indicated by the very fact of participating in absolution, even if the words themselves do not indicate intention. Relying on the verse "Do not defile" is based on the Gemara (Pesachim) and I do not see it as any more strange than many other laws. Although, in simple terms, it seems that it could also be a reference to a principle that is based on a Sabra or Tekna. Relying on the laws of vows is indeed more difficult, although considering the fact that the person is part of the community, the leadership of the community can perhaps be considered a collective vow (the actual leadership is no worse than a miracle. As a good custom that is repeated several times).