Teac NT 505 and Cary Integrated Si200.2D

Thought I would throw this out there. I recently purchased an integrated amp from Cary Audio, the Si 300.2d, and want to connect a digital streamer source. The Bluetooth Streaming source sounds really good with Spotify at highest resolution. It’s much more open and detailed and I’m really enjoying my CD collection again, but I would like to explore higher resolution music files and FLAC audio as well as consider a Tidal subscription. I have my eye on the Teac NT505, and with all the reviews being very positive, and at a good price point below the Lumin T2, I thought I would start this journey with this streamer/DAC with an upgrade path to Aurender or Lumin or other if needed.
Interestingly, the Cary has an excellent DAC already. As a matter fact is the same DAC as the Teac. Its a Verita AK4490EQ from the Asahi-Kasei Microdevices Company, VelvetSound, and has a good reputation. Both the Teac and the Cary perform up multiple levels of upsampling for 768k/32 bit PCM and DSD512.
So my question and concern is: what am I gaining if I have the same digital analog converter in both devices? I realize the quality of the streaming sources is important, but which device does the DAC conversion? And Will the Cary device do it’s own additional signal conversion? Does it matter? Both devices will have the upsampling capabilities, and therefore is it redundant?

As an additional question, the Teac has RCA or balanced XLR outputs. Don’t understand the benefits of XLR, and the distance will be less than 3 feet. Which type of interconnect would one recommend?

Thanks for everyone’s input in this discussion...

edit:I tried to correct the title of the post for the Cary Integrated amp. It should be the SI-300.2d