Edelgard is an excellent tactician, field leader, and combatant. She can certainly hold her own against most fighters but up against one of the 5 dragon lords she would be no match. Artemisia’s time manipulation is on point and even aside from that she has tremendous attack power and defense. Edelgard will have a hard time dealing any significant damage when you factor in the high speed regeneration as well. There is just no path to victory. Artemisia wins.