I found this interesting and thought I'd share the differences in the different oaths according to positions.
President of the United States of America
Article II, Section 1, Clause 8:
Before he enter on the Execution of his Office, he shall take the following Oath or Affirmation:–I do solemnly swear (or affirm) that I will faithfully execute the Office of President of the United States, and will to the best of my Ability, preserve, protect and defend the Constitution of the United States.
The oath used today in congress, senate, and government civilian positions has not changed since 1966 and is prescribed in Title 5, Section 3331 of the United States Code. It reads: “I, AB, do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion, and that I will well and faithfully discharge the duties of the office on which I am about to enter. So help me God.”
The Oath of Office Commisioned Officers is as stated "I ___, do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter. So help me God. " (Title 5 U.S. Code 3331, an individual, except the President, elected or appointed to an office of honor or profit in the civil service or uniformed services)
The Oath of Office Enlisted personnel is as follows "I, _____, do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; and that I will obey the orders of the President of the United States and the orders of the officers appointed over me, according to regulations and the Uniform Code of Military Justice. So help me God." (Title 10, US Code; Act of 5 May 1960 replacing the wording first adopted in 1789, with amendment effective 5 October 1962).
I think that the loophole there is that Biden isn't the President. Trump is. Biden wasn't elected. His position is forged making his authority null and void.