Is the ablution considered valid if the right hand was washed twice inadvertently, and the second part of the washing was omitted, then the ablution was completed, bearing in mind the suffering from scrupulousness regarding ablution?

This ablution is valid, and it is not invalidated by the incomplete washing of the right hand because it was already washed previously. This does not violate the sequence, because returning to wash a part of the right hand is not considered. It is as if the head was wiped after washing the left hand, and this is the required sequence. The most effective cure for obsessive doubts is to ignore them.