Amistad Project points out that the "safe harbor" date and other dates before Jan. 20 are not Constitutional. They were only set up for convenience sake.
https://mma.prnewswire.com/media/1359230/Electoral_College_Deadlines_White_Paper.pdf?p=pdf (https://mma.prnewswire.com/media/1359230/Electoral_College_Deadlines_White_Paper.pdf?p=pdf)