The Adhān of 'Uthmān is not applicable in our times:

Sheikh Albāni raḥimahullāh said: “We do not see following what Uthmān radhiyallāhu anhu did at all - without any restriction. Because we know from what has preceded that he only added the first Adhān because of a rational reason; which was due to the increased numbers and due to the settlements becoming distant from the Prophet's masjid. So whoever overlooks this reason and sticks to 'Uthmān’s Adhān unrestrictedly, he has not imitated him, radhiyallāhu anhu. He is in fact opposing 'Uthmān...So, following him, radhiyallāhu anhu, is only true when the reason for which 'Uthmān introduced the first Adhān is achieved, which was due to “the large number of people and their homes becoming distant from the masjid,” ​​as previously stated. الأجوبة النافعة عن أسئلة لجنة مسجد الجامعة " ( ص 20 )