Budding audiophile/vinyl questions

CD "quality" is a problem. The sampling rate 44.1 khz is too close to your hearing range. You may not be able to hear the high frequencies but they do affect the lower ones. This may be the "warmth" issue.

Another problem with CDs is the samples are made Right-Left-Right-... sequentially. Your ears are extremely sensitive to the timing of the sound waves hitting the different ears. This is how you locate the sound. Either the sampling rate needs to be a lot faster or it needs to be parallel somehow.

MP3s slaughter the sound information when it gets encoded.

Every time analog tracks are transferred something is lost. Once it is in digital format is will only change if it is converted to a different format. Excepting damage, of course.