IMHO adding a DAC is a better option. IMHO the digital cable is way more important then the transport. I tried six different transports and the bigger system improvement came from a better digital cable. That being said, there is a CAL Alpha tube DAC on the Gon now for $600, offer $450 and get some NOS tubes, or find an Electrocompaniet DAC or better yeet find a used older Audio Logic tube DAC. These will better any CDP in the $5000 range with a good digital cable and your current CDP.
Happy Listening.
Happy Listening.