I see this very clearly, I do think that Ámbar at some point had a crush scare, like she was questioning her feelings for Emilia, but eventually found out it wasn't romantic/strong enough
So obviously Ámbilia had a thing during the end of S2 and the start of S3. So here is a theory:
For Ámbar, it was much more to get some steam off. She enjoyed hooking up very much, but she also just did not want to be in a fully committed relationship. She was more into "hang out, get spicy, repeat"
Emilia was the same. Except that she, after a while, felt like she had actual feelings for Ámbar. And so, she pretended to like Matteo in hopes of getting Ámbar jealous, or show her that "she, too, liked a boy". But really, she just wanted something more but she knew Ámbar wasn't interested like that...