I played through a little bit of your mod (i didnt go far yet, but i love reading the new recipes) and read the description of planned features and the idea of going back to volcanus/gleba/fulgora had my mind racing with ideas that i want to suggest to you if you want to hear them.
apollo-you seem pretty set up to have uses for titanium, and a lightweight rocket hull seems fitting if you werent making it already.
Gleba-this one might be a bit ambitious to fully impliment, but in the place of the vanilla "growing wood on nauvis" thing, you could add a greenhouse unlock that turns carbon dioxide and water into wood, but after aquilio you find new ways to bioengineer some gleban organs/fungi to grow in the greenhouse and can assemble a living space station that will eventually be a half-alive moon to gleba, with organic tendrils grabbing asteroids and pathogen labs that digest ores more efficiently than any artificial ore processor could hope to chive
Volcanus-certain parts of any space ship will be pretty fireproof, like solar panels, but the sections of the hull will need to be replaced with a tungsten steel variant to avoid taking fire damage when travelling to a new location close to the sun and collecting tritium or helium-3 from solar flares and unlocking some fusion engines and unlocking the fusion reactor, and maybe developing yamato cannons as an alternative to railguns. Spent fusion cells could provide a new source of lithium, abeit in small amounts.
Fulgora-maybe there could be a new hard requirement for cerys transpleutonic to be installed. cerys could use the kind of changes this mod introduces and transpleutonic does exactly what it looks like youre hoping to do, from the changes in nuclear power so far.
(also, your factorized intermediates could really make lasers an interesting mid-late game intermediate product given the many different kinds and the many different uses, from laser turrets, to fusion reactors, to something in the circuit processing chain, to SILEX enrichment, to cleaning rust off rusty metal