Is the worship of one who fears punishment, does not believe in the existence of Allah with certain faith, and worships Allah under duress, accepted?

Allah Almighty created humans and jinn to worship Him and to test which of them is best in deeds. He did not create them in vain. The existence of Allah Almighty is an innate truth upon which all rational people agree, and it has only been denied by those atheists who deviated out of stubbornness and arrogance. Worshipping Allah while doubting His existence is of no benefit, because doubt nullifies the covenant of Islam. Therefore, repentance and renewal of faith are necessary. To remove doubt, it is recommended to read the Quran with contemplation and reflect on the verses of Allah, and to read specialized books on faith and creed.