Pretty sure her species is/was naturally amphibious. In her lore, there’s references to “the currents, the climes, the tides” as well as stone, air, and water. It’s not definitive, but it definitely feels to me like they’re a species that’s equally comfortable/capable of air or water.
As for Alani going into the isolation tank, keep in mind that she’s used to being on a planet where water is everywhere so that she’s used to being able to plop into the water for a swim whenever she felt like. She’s pretty much all dry now (since no one else can breath water, afaik) so she goes there to get some of that feeling back (there’s also a tragic melancholic element, in my mind, since she’s mourning the loss of her planet and people). Being able to swim and be in water is normal to her, even if it wasn’t constant, and she wants some of that normalcy back.
Of course, whenever I think too hard about Alani’s species or Akopos, I give myself a headache. How does a freshwater planet work? Oceans are salty because Earth is a rocky planet and water is the universal solvent (e.g. it’s salty because rocks are salty and water has little bits of rock in it). You can’t have a freshwater planet that still has dry land. But we’re outright told it’s a freshwater ocean planet (which is why the Jennerit were all “oh nice!” about it). For her species, why are her gills on her ribs (which looks cool but doesn’t really work with a rib cage) instead of on her neck (which is meaty and could easy develop a valve to prevent air from entering the water breathing parts and water from entering the air breathing parts). Also, why does she wear loose cloth clothing which would get waterlogged and unmanageable in water (which also brings up the whole issue of hair)?
Gonna stop myself there. Headache.
As to the OP, I suggest checking out the Sufficiently Advanced Bamboo Technology page on tvtropes, which is what the Eldrid use. They have super awesome technology that is designed to meld with and be indistinguishable from nature or seemingly natural processes. Basically, not only is their technology on par with or better than the Jennerit, it’s so amazing that it doesn’t even look like technology.
Even some of that gives me a headache when I think about it too much, like how do you ensure stable information storage when you’re storing the information in the junk DNA of a tree/plant (you can’t store it in the functional DNA because then you’re telling it to stop being a tree)? The entire reason a vast majority of our DNA is junk DNA is because that’s how you become immune to/resistant to viruses. Are the Codex trees somehow immune to all viruses? Do viruses simply not affect Codex trees? Do they have some kind of internal information validation system that makes sure that information isn’t modified when a virus occurs? If so, how does it work?
Once again, gonna stop there. Only headaches and rants go down that path.