@joekapahulu You are getting some interesting advice here most of it not really addressing your primary concern...practically no music service availabilty limit, modest cost and something Momma can enjoy without asking you for assistance everytime she wants to listen to music. Hopefully I got that right. I’ve been in your shoes and what I use in my system is the Sonos Port and a Sonos Connect (gen 2) in two of the systems in my home.The Sonos Port has decent sound fidelity is it the best no, but it will surpass the Marantz ND8006 sonically. I cannot think of a music service it does not have on offer,world wide radio and is a roon endpoint and can access your music libary on a desktop or server.When my kids and grandkids come to visit they can use our audio gear via Sonos and listen to thier own music they all know how to use it even my youngest grand. Another thing or question not mentioned by anyone thus far is do have you easy access to ethernet or does the streaming need to be wireless?, as is the case for me yes it does and Sonos checks that box. If not most of what is being suggested to you is going to another PITA for you, running lan wires and remote modules for example etc. (you get the picture) ie another possible pain point.
If your system is not high end (no mention of the other gear in the chain) a 2k+ streamer is a waste of money (you will not likely hear great distinctions) unless you plan to upgrade your system in the future and possibly be back to square one with your wife being hands off if she is like mine. If you read the between the lines there is a lot of rah rah for my purchase here not really addressing the question you actually asked which is often the case, a lot of folks go outta space quick here.
Go the simple route get a Sonos port it will check almost all your boxes for the family and services available, not break the bank and the app is very easy to use.If high quality sound is important to you you can still go the high end streamer route and have two boxes down the road like I have in one of my rooms. the Port is small enough that you’ll hardly even notice it is there set it as the default in your setup for your family and the better streamer for "deep" listening when you want to do that and there will be peace in your valley.
Been there done that...