Is a person considered a polytheist if he swears by other than Allah Almighty, while knowing the prohibition of that, but he did not intend polytheism, rather his tongue became accustomed to this type of oath, along with his acknowledgment that Allah is his Lord and that he is His servant?

It is impermissible to swear by other than Allah, and it is a minor shirk (polytheism). Repentance from it is obligatory, and no expiation is required. It is not from the understanding of fiqh (Islamic jurisprudence) to swear by other than Allah while knowing you are lying; rather, the obligation is to speak the truth. Abdullah ibn Mas'ud said: "To swear by Allah falsely is more beloved to me than to swear by other than Him truthfully." It has been reported that one who swears by Allah falsely may be forgiven by sincerely uttering "Lā ilāha illā Allāh" (There is no god but Allah).