@Arso, 1) you maybe right about pshat in rashi, but why do you say that’s the only pshat on the gemara. See kungres שמו של משיח will haskama from rav britewitz from אור שמח, he goes into pshat in rashi and comes out moshiach can be someone else from the dead. Also there are other rishonim who say so as we see from the following gemara it can be someone else (it’s also a medrash and Zohar)
ירושלמי ברכות פ”ב ה”ד
רבנן אמרי אהן מלכא משיחא אין [מן] חייא הוא דוד שמיה. אין [מן] דמכייא הוא דוד שמיה. אמר רבי תנחומא אנא אמרית טעמא ועושה חסד למשיחו לדוד.
The Rebbis say: This King Messiah, if he is from the living, his name is David. If he is from the dead, his name is David. Rebbi Tanḥuma said: I am declaring the reason (Ps. 18:51) “He gives kindness to His anointed, to David.’
