iOS App and VoiceOver: Audio Player almost unusable


I have a blind friend who is accessing my NextCloud instance through the Web interface and the iOS app. He tells me that the audio player of the newest release is almost unusable with VoiceOver.
Does anyone have more info about this problem? Whom should I contact at NextCloud to illustrate the details of the problem? My friend is what I would call a “power user”, so he could provide precious input to improve the accessibility of the iOS app.