Just going off pgr lore/spoilers, read at your own risk because i don't feel like filtering shit

Setting and agents

• There's alternate dimensions in the same level stacked like "layers", then there's a higher dimension.
• When civilizations in the lower plane get too close to breaking certain "rules" (so far we know about trying to survive the heat death of the universe, obtaining infinite energy and time travel), a "harvesting agent" is deployed to consume the civlization and take all the data to the transdimensional "gate" for the higher beings (THEM) Thanks to ch31 having an actual reviewed TL we know that Zero Point Energy is what triggers the contaminating/harvesting agent.
  • Time travel/transmission of information to the past are results of ZPE application
• The agent will target the most advanced technology the civilization in question has and corrupts it (i.e. your most advanced tech is making jelly donuts, so what it does is turn your jelly donuts into cabbages filled with spiders)
• The harvesting agent is divided into an "authority" which is the part that turns the donuts into cabbages, and an AI/Consciousness which helps control it.
• It's possible to mess with the harvesting agent by doing things like separating the consciousness from the authority or implanting it with concepts like being a fujo that thinks Zani won't be a giga for you submissive shy overworked office lady
• Even if the consciousness gets a personality, it will still keep the base instinct of "consuming/corrupting" (from what we've seen so far)
• You can destroy the consciousness but the authority will just create a new one in due time
• You can take over the authority, but if the consciousness doing it is too weak it will be destroyed.
• If you leave your layer it will try to follow you wherever you go

Observers/Gatekeepers/Ascension

When an individual/civilization meet certain requirements, they can take on a trial from the "gate, this is just a term used for reference, it's more like the point in existence between the lower dimensions and the higher dimension where things like time don't work like we know. If they pass it they earn the right to transcend and become higher beings.
It doesn't matter if it's a human/machine/whatever, so long as the consciousness meets the requirements they can transcend.
There are entities that passed the trial but are still trying to save their own doomed civilizations as well as looking for fit individuals to work togeher to save their shit together.
But THEY are very touchy about what's done to interfere/help in the lower dimensions and transcending puts you on THEIR radar so what you can do is limited

My theory is based on the ideas above, the cbt cinematics, the Black Shores plot and what we know so far about the waveworn phenomena.

Option 1:

• The He civilization fucked around and got marked for harvest, then went into hiding
• They made Thetys, ROV+XXX+SHO as well as the sentinels
• You (Rover) gotta figure out how to solve the shitshow while they're hidden/preserved
• During this a new civilization developed
• The goddess is an individual from either He or the new civilization who passed the trial and became an Observer/Gatekeeper, she's trying to save everyone

Option 2:

• The He civilization fucked around and got marked for harvest, left their home layer and came to SOL3
• The agent followed them and they got consumed, but the lament is still eating SOL3 because that's its job
• Thetys, ROV+XXX+SHO as well as the sentinels were made but deployed too late for He. Now they're trying to stop the lament and save the native civilization
• The goddess is an individual from either He or the new civilization who passed the trial and became an Observer/Gatekeeper, she's trying to save everyone left

Regardless of the option, Rover's consciousness was either qualified from the start, or got to that point and he's able to interact with the goddess, their plan could be either creating a vessel to contain the harvesting agent's "authority" and control it at will, or take the current harvesting agent consciousness, and implant it with concepts that will make it give a fuck about the civilization and not consume it.

Abby/Abraxas is either the original consciousness we messed with and we're absorbing threnodians to reclaim the authority part of the agent, or it's the vessel and we're taking the authority over from the original consciousness.

But why did Rover mindwipe?

Rover could have known that they'd spend more than 20 years in the gate and came up with the mindwipe excuse, then when in the "gate" they chose to return back to a point in the "past", bringing information from the future is a no no, so a memory wipe was necessary. Or they didn't spend more than 20 years but it's necessary for them to have a new perspective on everything, including Abby/Abraxas (this checks out more with what we know)