The Idolators believe in Tawhid Ar-Rububiyyah, which requires them to believe in Tawhid Al-Uluhiyyah

Allah states that the fact that He is One and that He is independent in His creation, control, dominion and guides one to realize that there is no God except Him and that none should be worshipped except Him Alone, with no partner or associate. He tells His Messenger Muhammad ﷺ to say to the idolators who worship others besides Him, even though they admit His Lordship, that He has no partner in Lordship. But despite this they still attributed partners in divinity to Him, and worshipped others besides Him even though they recognized the fact that those whom they worshipped could not create anything, did not own anything, nor do they have any control over anything. However, they still believed that these creatures could bring them closer to Allah,

مَا نَعْبُدُهُمْ إِلاَّ لِيُقَرِّبُونَآ إِلَى اللَّهِ زُلْفَى

وَلَقَدْ أَخَذْنَاهُم بِالْعَذَابِ فَمَا اسْتَكَانُوا لِرَ‌بِّهِمْ وَمَا يَتَضَرَّ‌عُونَ

And We have already seized them with punishment, but they did not turn humble to their Lord, nor do they supplicate in humility. (23:76)