@RSo. “and the Rambam, in Peirush Hamishnayos (Sanhedrin 10:1), writes that whoever says Mashiach will not be a descendent of Shlomo is “kofer BaShem uvedivrei neviav””
I dont wanna argue with haRambam or even Chazal (where it says from Zerubavel – not like Yermiyahu’s curse), but the Gemara says Bferush that Rebbi Yehuda Hanasi could have been Moshiach, and also says Bferush that He was a descendant of Shefatiah ben Avital (Avital was one of David’s wives).
So, no, He does NOT have to be from Shlomo