A kind of seven in the singular

Hello Rabbi! And congratulations (belatedly)
On Shabbat 24: It is written that the Shatz who descends to pray the evening prayer of Yot that falls on Shabbat only seals the Sabbath temple without mentioning Yot.
First and last, they were precise about the phrase “Shatz” that an individual cannot say and that it is only said in the minyan to which Shatz belongs.
The pharmacist cites from the geniuses that only one can say this (I did not find this in the geniuses, but this is not evidence).
I wanted to offer an explanation for the reading of the Ge’onim in the Gemara and ask whether you think it is acceptable :
If the phrase “Shatz” were not written, we would not be able to understand that this is a blessing from the spring of Sheva and we could think that it is a blessing from the Temple of Shabbat in the middle of the whisper prayer. Therefore, the phrase “Shatz” only comes to the Epoch of this understanding and to teach that it is a blessing from the spring of Sheva. There is no need for further study of this phrase. And perhaps this is how Rashi learned there, “The messenger of the public who descends from the Arab – the one who prays the blessing from the spring of Sheva buys heaven and earth from the fathers with his word” from the beginning speech, it is possible to understand that the entire meaning of the phrase Shatz is that it is a blessing from the spring of Sheva and not to the Epoch of a single person.