Best way to get Mystery of Elder Continent?

Hi! [li]
I have ~150 jade and ~200 relics of the third city. I’m at persuasive 51, watchful 34, everything else <5. What would be the best way to get the Mystery of Elder Continent?

Item conversions on the Myself page - 50 Relics of the Third City gives 10 Mysteries of the Elder Continent (you need some connected Tomb Colonies) or if you have 50 Visions of the Surface you can get 51 Mysteries of the Elder Continent.

Judging by your profile you might not know about this:

login using that link to get 500 or so mysteries

Bless you, Sir Waffles54.