The Old Testament ceremonial law was the wall that separated Jew from Gentile. It was given by God, yes; it was given to teach, yes; and Jews should have taught it to Gentiles if they would receive it, but it was a separating factor.
Sometimes well-meaning Jewish people who have been converted get together in a church on their own, a Jewish church. They may update some of the Old Testament ordinances, but they do things in a very Jewish way. Well, they may be converted if they truly believe the gospel and they mean well, but what they are doing is not right because we are now one body, one church, all having equal access to Christ.
Some people believe fanciful things. They think that before Christ comes or after he comes – they differ on this – then a temple will be rebuilt in Jerusalem and Jews will flock in, worshipping Christ in that temple. That is fiction, not the Bible. No, if numerous Jews are converted towards the end, they will come into the church as converted Jews and converted Gentiles together, all one in Christ Jesus.