As there was no prescribed insignia for this rank, General of the Armies of the United States, General Pershing chose the four stars of a full general, except in gold. The rank has been argued to be equivalent to "6-star" general, as the insignia of the next lowest rank "General of the Army" is designated by five stars. According to the biography Until the Last Trumpet Sounds by Gene Smith, Pershing never wore the rank on his uniform.
Then in 1976, Congress posthumously appointed General Washington to the grade of General of the Armies to out rank them all.
I saw that- and it’s very confusing because it was designated by the Four star insignia. And the difference is General of the Armies vs General of the Army.