Ruling on building over graves, plastering them, and writing on them

Your Eminence! Is the shape of the grave a matter of worship in which it is not permissible to make changes? Currently, in some of our graves in Kuwait, they have placed raised marble slabs on them, and some of them write on them: [al-Fajr:27] Then they write the name: This is the grave of so-and-so or so-and-so. Are we commanded to worship in the form of the grave such that it is only sand and without any elevation?
What you mentioned about placing marble on the grave,And they write on it: [al-Fajr:27-30] and also the name of the man or woman, and perhaps the date of his death, this is reprehensible and forbidden, and it must be removed; because the Prophet (peace and blessings be upon him) (forbade building over a grave, or writing on it, or sitting on it, or plastering it) and he sent 'Ali ibn Abi Talib (may Allah be pleased with him) not to leave any elevated grave without leveling it -Meaning: making it like the other graves - so these people must remove the marble they placed. Convey this to them from me,and say: The scholars say: The deceased is harmed by the reprehensible act if it is done at his grave, and this is a reprehensible act. The implication of the scholars' statement is that the owner of the grave - the person buried there - is currently being harmed by what was placed on it. Act on this,and say: It must be removed. If they do so, it is a favor from Allah upon them and upon their deceased. If they do not do so, it is obligatory for the person responsible for the cemetery to remove it. Report this to the person in charge of the cemeteries and he will remove it.

Then what makes them know that it is a tranquil soul, for which it is said: (Return to your Lord well-pleased and well-pleasing) Who knows? Does everyone know that this man died upon the oneness of Allah and faith? We only know the apparent fact that he died, but we do not know about the matters of the Hereafter.