I can not research the "Planet discovery Arcanyx", it's red and unavailable.
The only requirement "asteroid collector" is researched.

I attached a screenshot of the only path to it being green, still the research itself is red: https://snipboard.io/CNWAME.jpg

How do we unlock this?

"

You're using some other mod that hides the landfill technology, which is also a prerequisite for Planet discovery Arcanyx. The other mod hides the technology but doesn't remove it from the prerequisites of other technologies so the research becomes inaccessible.