How can I fight the Jews with the intention of exalting the word of Allah and achieving martyrdom in His cause, not for the sake of the homeland or people's whims, if the fighting is to reclaim land?

If you become a soldier in an army that fights Jews or disbelievers, then purify your intention for Allah and aim to support Islam and for the word of Allah to be supreme. This will make your fighting in the cause of Allah, as the Prophet, peace and blessings be upon him, said: "Whoever fights so that the word of Allah is supreme, then he is in the cause of Allah."