Androids 5-9 were stable in this regard, in Android 10 the paths changed due to (enforced by Google) the "new" Storage Access Frameworks (SAF) API requirement to access files. For SAF you first hit that Enable button, find the desired storage and optionally a root folder and hit "ALLOW..." button. Depending on ROM, additional menu / Show Internal Storage selection is required + side menu should be used to select the target storage. Poweramp then either uses default Music/Downloads/Play