A high-bitrate 1080p file offers incredible clarity without the 50GB–100GB file size of a 4K disc rip.
Look for DTS-HD Master Audio or Dolby Atmos tracks. The sound design in Endgame is as immersive as the visuals.
Look for 10-bit color depth if your display supports it, which helps eliminate "banding" in the dark space sequences. A Note on Legal Viewing