I use Tidal and Pandora exclusively for my streaming.  Therefore, my very modified (Ric at Tweak Audio) Oppo BDP-103 to Decware ZDSD works beautifully.  I utilize the digital coax out on the Oppo to connect to the ZDSD which then goes out to my Decware amps.  

The other option I often utilize is my Onkyo DP-X1 DAP.  I like this player for its balanced output as well as the support of MQA and resolutions up to 384kHz/24-bit.  I had a cable made which allows me to connect the 2.5mm balanced output jack of the DAP to the XLR balanced inputs on the ZDSD.  The Onkyo DAP is great for files that the ZDSD does not support.  They both sound wonderful!

Correct!  On all possibilities.  There are also purpose build RAID storage devices that have firmware built in to allow it to function as a turn key media server out of the box.  It really all depends on your budget and/or your willingness to "build" the capability rather than a more out-of-the-box solution.  

If you are streaming hi-res from any media server over WiFi, you will need good signal strength and proximity otherwise you will be annoyed with buffering and choppy audio.  Powerline adapters are a great alternative to WiFi which allows you to connect via ethernet through your home's power lines/outlets.  You get line speed as opposed to the punished throughput that is inevitable with WiFi.  

yes jeff is correct on the wifi... stay away.  i've tried raspberry pi's, NUC's, and home built itx's.  the only one that's fairly stable is the NUC running Daphile with custom external antenna (it looks funny with 6" rabbit ears).  others only work via Ethernet.

i've got 2 players that i'll let go for a reasonable price if you want to play in this space.  take some computer skills to set up and keep them going (i taught myself and i am not a computer person).  pm me if interested.  i am not trying to sell them... there just sitting around doing nothing.

1) Raspberry pi with dac plus (built in dac) in plexi case.  os is volumino
2) home built mini box, itx mb (no fan or hd), pico psu.  os daphile

both boot from external sd card.

they'll play music off your server/network or external hd.  also there are add on apps to stream just about anything.  i use mine to play all my ripped flac file on my server.

i still play cd's but most of the time i want to sit on my rear and play tunes via smartphone interface/player.

cool thing is when people come over they can download a squeezebox app on their phone and play whatever they like!  then i don't have to be the dj.