As a user, I find it slightly confusing how the subspace creation UX avoids using the term 'subspace' entirely. In particular, these are the two points in the UI that feel the most incongruous:

When creating a subspace, seeing this image causes me to think "wait, am I creating the same space again, or something?" I feel that changing the wording to "Create a subspace" would make it more clear what's going on, namely that I'm creating a space to be nested inside the Tỏaq space. "Add a space to a space" sounds a bit strange as well.

Additionally, it feels strange that this menu says "Add space" instead of "Add subspace", since the current wording makes it less clear that the new space will be nested. The discussions in matrix-org/matrix-react-sdk#6458 mentioned a folder/file explorer analogy, though I think one reason that file explorers can get away with saying "Add folder" rather than "Add subfolder" is because in order to get to that action, you have to go inside a folder and click on the blank space within that folder, rather than clicking on the folder itself. The placement of the interaction itself makes it clear that nesting will happen, whereas the space UI has this interaction placed alongside the parent space.

This is of course general, subjective feedback, and can very likely be addressed in ways other than what I've suggested.