My advice is based on experience in traditional relationships, I admittedly have no clue how the whole non-binary relationship shit works so I apologize if this doesnt help.

1. The only relationships that last are between two people who are best friends.

2. Dont try to predict potential relationships based on individual past relationships because every person will react differently. (I see the irony of giving my advice based on my past relationships but really im providing generalizations from decades of my relationships and people in relationships who are close to me)

3. Worry less about where something is going with someone and spend more time enjoying what you have in the moment.

Hello, I'm sorry you are going through these feelings and I know it feels scary. I'd just like to say that it's very important for your mental health to understand your happiness doesn't depend on a single person. Remind yourself that even if they choose just to be friends, you will be okay. Hope this helps.

Growlers: Try Hard Fool

https://music.youtube.com/watch?v=QFTmEfWyzvY

Heres a song i listen to when im feeling anxious.

Putting too much thought and energy into these things can often backfire. Dont stop pushing the issue enrirely because if you arent comfortable at arms length, thats a discussion you need to have with isla for sure. But isla also needs (probably alot) time to figure out how they feel. its up to you to determine if its worth waiting and if isla actually intends to follow through.