Believing in the divinity of a human would fall under the idolatry prohibitions. There’s some question of how serious an issue this is. In particular, the major historical Rabbis who lived in the Christian world generally argued that the anti-idolatry statutes were more strict for Jews than they were for non-Jews, so it was ok for a non-Jews to believe this way but not a Jew. Those in the Muslim world took a more strong standpoint (presumably in part because they could get away with it and in part influence from Muslim beliefs) and considered this to be unacceptable for non-Jews also.
If one had one of the minority forms of Christianity that does’t believe that Jesus is divine, that would be less problematic. There are some who claim that the defining difference between Christianity and Judaism is whether or not Jesus was the messiah, but this seems to be very weak from a theological perspective, and is more useful as a descriptive rather than normative claim.
Believing in the divinity of a human would fall under the idolatry prohibitions. There’s some question of how serious an issue this is. In particular, the major historical Rabbis who lived in the Christian world generally argued that the anti-idolatry statutes were more strict for Jews than they were for non-Jews, so it was ok for a non-Jews to believe this way but not a Jew. Those in the Muslim world took a more strong standpoint (presumably in part because they could get away with it and in part influence from Muslim beliefs) and considered this to be unacceptable for non-Jews also.
If one had one of the minority forms of Christianity that does’t believe that Jesus is divine, that would be less problematic. There are some who claim that the defining difference between Christianity and Judaism is whether or not Jesus was the messiah, but this seems to be very weak from a theological perspective, and is more useful as a descriptive rather than normative claim.