Oh she has an interesting backstory! So I do have one idea. I’m not sure how well it could work but here it is. Maverick knew a celestial back then named Talia. Perhaps his celestial friend and Freya could have known each other and that’s how he met Freya? Then maybe he bumps into her or something in today’s time and she wont remember him. So he pulls out Talia’s necklace and that could spark a memory. So he then helps her try to get used to the time period?
Feel free to change anything or if you have another idea, I’d be happy to hear it!