Netflix
For Netflix your best option is to use the app in Web OS (same goes for Amazon). Your TV is capable of passing (compressed) Atmos through ARC should you ever decide to upgrade your amp and speakers to say a 5.1.2 set up. You'll also get Netflix in Dolby Vision for titles with DV.
1080p
If your ripped files are 1080p, download either the Plex or Emby app for Web OS. You'll need to run the Plex/Emby server on a PC or Mac. Output sound from your TV to your receiver.
4K
4K is where the above becomes a problem. Your TV only comes with 10/100 ethernet LAN port. Why not gigabit in this day and age I have no idea. You can play 4K using the method above but you will suffer from buffering and blockiness in some titles with high bitrates. Not recommended.
So if you watch a lot of 4K rips or intend to the following options work.
Option 1 - (best video - best audio)
Oppo UDP-203 (or any Ultra UHD blu-ray player
with DNLA)
Run Emby server on Mac or PC
Use Emby app on iPad or iPhone and steam to UHD player
Upgrade Amp to pass through 4K (Denon XVR-X2400 or similar)
203 to receiver, receiver to TV
Option 2 - (best video - best audio)
Nvidia Shield
Run Plex server and Plex client on shield
Upgrade Amp to pass through 4K (Denon XVR-X2400 or similar)
Shield to receiver, receiver to TV
Option 3 (best video - best audio)
Nvidia Shield
Run Emby server on Mac or PC
Run Emby client on Shield
Upgrade Amp to pass through 4K (Denon XVR-X2400 or similar)
Shield to receiver, receiver to TV
Option 4 - (best video - compromised audio)***
Oppo UDP-203 (or any Ultra UHD blu-ray player
with DNLA)
Run Emby server on Mac or PC
Use Emby app on iPad or iPhone and steam to UHD player
As your receiver does not pass through 4k send the picture and sound from the 203 to the TV. Output sound from your TV to your receiver.
***Edit/correction - use second HDMI out for audio to legacy receiver - (best video - best audio)
Option 5 - (best video - compromised audio)
Nvidia Shield
Run Plex server and Plex client on shield
As your receiver does not pass through 4k send the picture and sound from the Shield to the TV. Output sound from your TV to your receiver.
Option 6 (best video - compromised audio)
Nvidia Shield
Run Emby server on Mac or PC
Run Emby client on Shield
As your receiver does not pass through 4k send the picture and sound from the Shield to the TV. Output sound from your TV to your receiver.
An interesting article about upscaling...
Why your 4K TV is probably the only 4K converter you need