Could you please tell me the logic used for tiebreakers ? I can't figure it out.

It certainly isn't Head-To-Head or Division/Conference records. If it's meant to mirror the NFL, it's not working correctly in the game.

Thank you

Wins, Head to Head, Division, Conference, Points For, coin flip

There is some additional checks for 3-way ties... for wildcard there are shared conf opponents, and for non-wildcard it looks at common division and common conference.