Community Tip - You can change your system assigned username to something more personal in your community settings. X
Resolved by next code:
LWCNormalizedObject obj = new LWCNormalizedObject(persistable, null, locale, null);
obj.load(attributeInnerName);
String displayName = obj.getAttributeDescriptor(attributeInnerName).getLabel();
Resolved by next code:
LWCNormalizedObject obj = new LWCNormalizedObject(persistable, null, locale, null);
obj.load(attributeInnerName);
String displayName = obj.getAttributeDescriptor(attributeInnerName).getLabel();