I am over 70 and have followed the development of streaming / streamers over the last couple decades. It is not overly complicated, if you do not want it to be. The good news is that you can skip the many intermediary steps and go right to the highly reliable, high quality sound you can get today,
I have owned Aurlic Aries, and now own two Aurender. I have also heard the Rose and many others. I recommend Aurender. Conductor is a great app for control.
First it would be really helpful to know what other equipment you have. But assuming for now that you have high quality and high resolution equipment, then the sound of a CD, ripped file, stored file on NAS and streaming will sound exactly the same with a good streamer.
In general, streamers are like any other high end audio component in that you get what you pay for. So, you do not want to get a streamer with a DAC if you don’t need one because you will be buying a lower quality streamer (extra function you are not using and more noise and interference in the box). Also, you do not want to spend less... if you can get away with it unless you do not care about sound quality. My $45K vinyl leg sounds the same as my streaming digital leg. I don’t playback ripped files (although I have them on my streamer) or CDs... because they sound the same as Qobuz streamed music. Qobuz has over 10 million albums and over half a million are in higher than Red Book CD resolution. Years of delight and discovery and probably all of you old music.
So, I recommend as high a quality streamer as you can afford. In general, each jump in a thousand or so will result in better sound up to and beyond $20K. So you want to make sure your streamer is not your weak point (just and in vinyl playback). I have found that if you get the best in class for the money then the most cost effective investment is Streamer = DAC = Preamp = Amp... if you have vinyl also = phono stage = tt.
You are correct to want a good App to control your streamer. Aurender’s Conductor app is well respected and getting better daily. It works on iPhone, iPad and MacBook... I am sure on other non-Apple devices, Friends of mine have purchased other streamers... very expensive ones and complain about the app.
You get an Aurrender and you plunk it down, plug in the power cord, ethernet, preamp, and find it on your iPad. If you already have an Qobuz account (Yes, that is the one you want) all you do is logon once through the Aurender app and start playing music... no more fooling around. Done. Sounds like that is what you want.
You can get one with internal storage if you are bored and want to play with your computer. But you’re probably not going to be able to detect any difference in sound quality even with a bottom of the line Aurender N200. I would completely avoid antiquated means of playback: CDs, ripped CD, and purchased files.