This is one of the question best answered by yourself. What are you using camera for, in terms of technology why still consider DSLR like d7500 although it is perfectly usable and may be cost effective. If you mainly shoot video then a z30 is convenient but so is a z50 but it is a much more features packed camera in one body. Do understand Nikon is primarily focusing on fullframe cameras and their apsc cameras have minimum z mount lens support and you may need to adapt last generation F mount lenses . Nikon as a camera company is facing a challenging time Vs other camera companies and have not done much in terms of offering new technology vis-a vie the major competitors so what Nikon have done is to offer firmware upgrades to their camera bodies to stay in the competition. On paper z50 does everything so for a photo hobbyist it is more than adequate. Do know that ultimately it is not the camera but your knowledge and skills that determine the quality of your output although gear matters too. For people thinking about what camera decisions, this may give food for thought.
Good news, Nikon added eye detect for video in z50.