Export settings help>

I just exported a video using settings adobe recommended as a good balance between quality and whatever.
The file size came out to be about the same as the original. I had just stripped some audio out of a video file.
So why in God's name is the quality of the export vastly worse than the original? If I plugged in some settings someone online recommended as top quality, the file size would have been literally 10x bigger.
So why is this "premiere" software so utterly incapable of making a video of good quality without jacking the file size up immensely? Assuming that would have actually been good quality at all...I didn't waste hours rendering that one.
The original video is about 800mb and quality is immaculate. 1080.
What settings can I possibly use to match this?
Settings I used were basically matching the original, H264, source adaptive high quality bitrate...