I hope questions are allowed here. I am curios if there is a different sort of scientific calendar which does not use the birth of Jesus as a reference like AD and BC. For example Kurzgesagt's calendars use the the current year plus 10000 as this represents the human better or something like that.

Would there be a way to do this more accurately? How could we, in a scientific correct way, define a reference from where we are counting years?

Also I have read about the idea of having 13 months instead of 12 would be "nice" because then we could have a even distributed amount of days per month.

Are there already ideas for this? What would you recommend to read?