Yeah, from the bits and pieces we've heard I'm pretty sure the only MCU elements the Sony Spider-Verse movies are able to reference are ones from the Spider-Man movie.
Sure, yes, from a corporate/licensing standpoint, that's true. But the point is, it looks like Sony intends to portray its Spidey universe movies as if they take place in the MCU, rather than a separate reality. The MCU probably won't reciprocate, but that's the presumption the filmmakers at Sony want us to take away. So it's like tie-in novels, in a way. Sometimes a tie-in line only has a license to portions of the franchise it connects to and isn't allowed to reference anything beyond them, but its stories still purport to be set in the same reality as that franchise. (Like the way Marvel's post-TMP Trek comic was nominally forbidden to reference characters and storylines from TOS, though it still managed to sneak a few past the radar.)