When we speak of 'canon' we must ask who's canon? Surely everyone knows each branch of Christianity had its own collection of writings and this in a diminished way continues today. All of the discussion above is focused upon a Proto-orthodox branch that dominated in later centuries. The Nag Hamadi library should illustrate that point. Christianity went through a bottleneck; all earlier forms of Christianity were lost under the domination of the 'Catholic' form. All branches today spring from it.
Many have elevated the Muratorian list as just the proof they needed to suppose an early consensus. It's not sober objectivity that leads to that conclusion. The Muratorian fragment list was redacted in the 8th century, when previous version/s were written is unknown. Some speculate the late second while others see very good reasons (it's use as a prologue, it's Latin reflects an earlier Latin vorlage not Greek, it's lack of mention by earlier heresiologists and writers, etc.) to date it to the 4th.
see: The Muratorian Fragment: Text, Translation and Commentary” (Mohr Siebeck: 2022)
The fragment itself demonstrates that hundreds of years later than the supposed date of Jesus, even the proto-orthodox branches of the faith had not yet agreed upon what writings were approved.