I think a counterargument would be parallel evolution: There are various examples in nature, where a certain feature evolved independently several times, without any genetic connection - from what I understand, we believe because the evolutionary pressures were similar.

One obvious example would be wings, where you have several different strategies - feathers, insect wings, bat-like wings, etc - that have similar functionality and employ the same physical principles, but are "implemented" vastly differently.

You have similar examples in brains, where e.g. corvids are capable of various cognitive feats that would involve the neocortex in human brains - only their brains don't have a neocortex. Instead they seem to use certain other brain regions for that, which don't have an equivalent in humans.

Nevertheless it's possible to communicate with corvids.

So this makes me wonder if a different "implementation" always necessarily means the results are incomparable.

In the interest of falsifiability, what behavior or internal structures in LLMs would be enough to be convincing that they are "real" emotions?