What if Loki ends up creating a branch reality, one in which he unintentionally (or intentionally) encourages young Agatha to pursue dark magic in the first place.
So in his travels, he could find himself in 1600s Salem, Massachusetts, where a young Agatha Harkness is only just learning about magic.
It’s definitely only a fan dream at this point, but Loki’s time-travel bent could certainly allow the two to meet at some point in time.
This hypothetical meeting could also have major ramifications on Harkness.