Im personally not sure if it would transform it into chakra or just take the raw energy, but I'm leaning towards it being only chakra, however if you get enough chakra you could probably alter the tree so that it only takes raw energy or what you specifically want like magic,meta gene etc.

Normal earth is psionics fruit. Because of brain focus.

Kryptonyan is solar fruit.

Mars is adaptive fruit.

Hm...dunno. If it can absorb energy than it should be able to convert it.

We don’t know much about the God Tree but I think it depends on the Ōtsutsuki used to make it, like Momoshiki could convert others into chakra so a tree made by him could absorb in a place with no chakra and then convert it into chakra but since we have no real idea how the god tree functions we can’t say for sure, it’s all theories currently. In Boruto it gets more complicated since we don’t even know much about the 2 pieces used to make the God Tree, the Ōtsutsuki clan is nearly a complete mystery and the Ten Tails gets more complicated every time we see it like how they just split off and then mini Ten Tails ran around turning people into trees

The chakra fruit absorbs physical energy, not necessarily spiritual. The more present life/energy, the more potent the effect. It's why Kaguya became so powerful after eating earth's fruit. That being said, there's no indication that eating a fruit grants power of the people within. Further, in both the cases of Krypton and mars, the fruit would likely be vastly weaker. Both because the life within is scarce, and because in case of Krypton, the planet is already on its last legs.

Hope that answer your question.

Maybe 🤔, or it could be a form of energy similar to Chakra

That’s actually an interesting question.