What harm can Anonymous Instagram account do in my iPhone using the official app?

Hi,

I closed my IG account where I obviously were not private about my day to day life. Now Im more privacy minded and was thinking on creating an anonymous IG account to follow some interest like hobbies and some fan art. What can IG do in my phone under this scenario? It say can read my device ID but Im not sure if is bad.

What do you think?

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