Another option is putting a network switch after the 45' run of ethernet cable, run by a linear power supply.
Some form of LAN Isolator to the Lumin with a good ethernet cable from the switch. An Eno would suit, or the likes of a Pink Faun.
What can I do between the wall and my streamer/DAC?
I have AT&T fiberoptic internet and the AT&T supplied router. I then have generic ethernet cable to the music room in the basement to the back of my Lumin T2. Is the anything I can do to make this a better sounding situation? I feel it sound very good as is, just wondering if I am leaving some goodness on the table with this set-up, Thanks, Allen.