Here is an article that discusses the topic quite broadly [0]. The most relevant section is part 4.

I will freely admit that it actually refutes some of my claims - that's are actual example of simple syntax identified in several species.

Still, I believe it matches my broader point: there are a fundamental, measurable differences between human language and animal calls, with the latter at best showing only very basic structure, if any.

[0] https://royalsocietypublishing.org/doi/10.1098/rstb.2019.006...

I will readily agree that levels of sophistication of languages vary, and that human languages are almost certainly the most complex / sophisticated that we know of.