Volume seems too low

My preamp levels with LPs go up beyond other line level sources (noticed it more when I switched to a lower powered tube amp), but since the preamp and phono preamp are so clean it doesn't matter much. Your issue seems extreme though so I agree that it's likely a cartridge gain issue...or phono preamp issue. If it's not LPs that are the issue it's time to send the amp in for repair maybe.

I am not playing LPs. This is with CDs.

what is your source? what is your amp and what are your SPEAKERS?

All depends on how efficient the speakers are, and how much power the amp has.
2/3 is no big deal, and is way way better than barely cracking the gain knob.
So I would say be happy don't worry. And go back to enjoying the music.

(Only if this was a new sudden change from same equipment behavior previously then I would worry)

Ayon triton iii integrated. Ayon cd 07s. B&W 686 shelf speakers (need new speakers).