Hi Max,
Can you please check the same with another theme? I don’t think the issue is from plugin.

Yes, these two are not behaving correctly together as the theme has managed to add css for the known parts of the BuddyPress(default elements).

Since the plugin is not part of BuddyPress, the theme does not explicitly supports it.

Even if I give you some css, It won’t be sufficient and it may cause problem with the cropper. That’s why I asked you to get support from theme developers. They know the ins and out of theme and can provide the support for the plugin out of the box.

Please do know the responsiveness is mostly dependent on how the theme behaves(except in a few cases). I can still help you with css and media query but I may not be able to guarantee that it won’t break the cropper. The root of this is the theme using a large size of avatar.

Regards
Brajesh