Does the ḥadīth "Indeed a man may perform the deeds of the people of Hellfire until there is nothing between him and it except an arm's length, then the decree overtakes him, so he performs the deeds of the people of Paradise and enters it" (and in one narration: "in what appears to people") contradict the ḥadīth "When Allah loves a servant... then acceptance for him is placed on Earth"?

There is no contradiction between the hadiths, for the worker who performs the work of the people of Paradise, but is not beloved by Allah, his apparent work may be righteous, but his heart contains evil intentions and hidden wickedness. For a deed is judged by its end and its conclusion, and this worker did not persevere in his work until he completed it due to an inherent flaw and a blemish that led to his downfall at the end of his life, and that flaw betrayed him. Had there been no deceit or flaw, his faith would not have turned into disbelief and apostasy. And Allah knows about all servants what some of them do not know about others.