Why did the Muslims take the Qur’an from Uthman ibn Affan, even though the Prophet ordered that it be taken from four others, and why did Uthman gather all the Companions to compile the masaḥif, and not limit it to the four mentioned in the hadith?

The Hadith "Take the Quran from four" means receiving and mastering it from these Companions, not that it was exclusively limited to them, for many were حافظين (memorizers) of the Quran. The compilation of the Quran occurred in stages: during the era of Abu Bakr, it was collected from the حافظين (memorizers) and from what was written, then during the era of Uthman, these codices were copied and distributed to the major cities. This differs from the collection of the Quran itself, which was a collective task, whereas the Hadith refers to taking and learning from these four due to their precision and mastery.