Bozjan lore is properly scuffed.

[Ashlyn_Ishina]

A lot of Bozjan stuff is kept behind the Bozjan Resistance quest, Shadowbringers' relic weapon questline "Save the Queen."

Simply put, Queens Gunnhildr were not chosen how you'd think. Bozja was a highly stratified caste society (real original, Matsuno) where when it was necessary a woman from the shaman caste would be raised up to Queen Gunnhildr. So it's entirely possible for there to have been a "Queen Gunnhildr" during the time of the Imperial invasion despite the Queen Gunnhildr contemporary to Allag's fall being long dead.

Said Queen Gunnhildr was also a puppet ruler instated by her praetorian guard, Gunnhildr's Blades, to protect Bozja from being destroyed by offering herself as a sacrifice to summon a primal with Save the Queen since the old one was too scared to do it. Surprise, she had the Echo, so they killed her because with her power she was now a threat and would be doubly so if she learned she was intended to just be a sacrifice.

I already said all of this within my first post, which shows that the Bozjan lore is scuffed cause it has two conflicting primary sources.