@ARSo
Proclaiming to Klal Yisrael by force of a full-fledged Prophesy that RMMS has arrived to irrevocably take klal yisrael out of galut is an as clear as possible claim to the messiahship.
A claim which has to verified thru results and reality.
If there is a second coming and a second chance , then there is NO VERFICATION at all.
I am just elaborating on the words of RAMBAN and RAMBAM.
And there is zero connection to the gmara in sanhedrin , as mentioned.