Is it permissible to eat food offered by a shrine where polytheism is practiced, and is the salary paid for working there lawful?

What some people do, such as venerating graves by building mosques and domes over them, lighting lamps, supplicating to the deceased, asking them to fulfill needs, and offering vows to them, is considered a violation of religious texts and manifestations of major polytheism (shirk akbar), as stated in the hadiths: "The curse of Allah be upon the Jews and Christians for they took the graves of their prophets as places of worship," and "Those are the worst of creation in the sight of Allah on the Day of Resurrection," and "Do not leave any statue but you obliterate it, nor any elevated grave but you level it," and "The Messenger of Allah (peace be upon him) forbade plastering graves, sitting on them, and building on them."

Therefore, it is impermissible to work in the service of these shrines, and the salary received for such work is unlawful, based on Allah's saying: (And He has already sent down to you in the Book that when you hear the verses of Allah being denied and ridiculed, do not sit with them until they enter into another conversation. Indeed, you would then be like them. Indeed, Allah will gather the hypocrites and disbelievers in Hell all together) [An-Nisa: 140].

As for the foods offered at the shrines: 1. Sacrifices vowed to the occupants of the graves: It is not permissible to eat them, because they are offered to other than Allah, and this is major polytheism, as the Prophet (peace be upon him) said: "Allah curses whoever sacrifices to other than Allah." 2. Foods and money vowed to the occupants of the graves: Their vows are invalid because they are vows made to a created being. They must be returned to their owners if they are known; otherwise, they should be given to the poor and needy, and they are not permissible for the wealthy. 3. Foods and money given as charity to the visitors of the shrines: These are permissible for the person to whom they are given, and it is permissible for him, his family, or his guests to eat from them.