What to unlock next
Points are always scarcer than technologies, so this answers one question: what to spend them on right now. The order is explained below, and nothing here is invented: every number comes from the game files.
Already unlocked 0
Sorted by how much one point buys: items and structures unlocked, divided by cost. The game does not say which item matters more, so neither do we.
These words are ours, not the game's: Level. Everything else on this page is the game's own wording.