Yeah, honestly a 2.0 track that’s properly dolby surround encoded can sound fantastic upmixed. Better even than a 5.1 ac3 track because each channel can have more bits to it. To me a 2.0 track that’s encoded with a high bitrate will sound much closer to a dts track than a 5.1 ac3 track. That’s just my ears though, some may not agree but to me discrete channels is whatevs, surround is an immersive effect and a little channel bleeding and a little dialogue bleeding into the front left and right channels don’t diminish the immersive effect one bit, but the compression artifacts of 5.1 channels crammed into an ac3 do. Ironically on my setup the 2.0 tracks even sound warmer and have more bass.

(My receiver has a really good sound for movies but oddly enough can’t do dts so I always transcode it to a dolby surround pcm instead of 5.1 dolby and it sounds better than a dolby digital track at 5.1 would)