Is every deity worshipped instead of Allah considered a Taghut, even if the worship does not render its perpetrator an unbeliever?

Directing any act of worship to other than Allah the Almighty is Shirk (polytheism), even if it is a single act of worship like a prostration. Whoever does that becomes a disbeliever and a polytheist. Allah the Almighty commanded that worship be for Him alone, such as supplication, fear, hope, reliance, and other acts. The proof for this is His saying, the Most High: "Do not set up with Allah another deity, lest you sit disgraced and abandoned." (Quran 17:22) And His saying: "So whoever hopes for the meeting with his Lord, let him do righteous work and not associate in the worship of his Lord anyone." (Quran 18:110) Scholars have also affirmed that directing any part of worship to other than Allah makes the doer a polytheist and a disbeliever, citing His saying, the Most High: "And whoever invokes with Allah another deity for which he has no proof – then his account is only with his Lord. Indeed, the disbelievers will not succeed." (Quran 23:117) It should be noted that seeking knowledge should be through systematic study, not merely by posing questions.