When the qiblah changed, the jews made a ruckus about this, so Allah says that no matter what proof you bring, they will not accept.
This ayah is an indication that the qiblah will never change again after this.
The Christians have got their own qiblah, the jews have their own, so they dont agree even amongst themselves.
The ahlul kitab recognised the Prophet ﷺ as they would their own children.
The ahlul kitab did not accept due to hasad, they didnt want to leave their book.
When Ibrahim a.s. Made dua that the prophets remain in his bloodline, all of the prophets were put under the lineage of Ishaq, and the Prophet ﷺ alone was under the lineage of Ismail.
Their scholars knew, but they hid the truth on purpose.