Hello Op
You have a great start to your system but you will find over time you will continue to chase the elusive dream of perfect sound for the rest of your life. Yes, a good Power Conditioner will help. I have an Inakustic 3500P. Yes, a good Power cord will help and so will interconnects. Even a great fuse will help a lot in your system.
As others have mentioned speaker placement is important and a no-cost option. Room treatments are really important depending on your room. Do you have bass boom or echoing?
I had the Lumin U-1 mini, D-2, A-1 and X-1 Streamer / DAC's. As you go up the line each improved my sound dramatically. Now I have a Lampizator Pacific DAC and Lucas Audio Music Server and my SQ is several notches up. And if you go to tubes, just changing the tubes can alter the sound.
I have been testing multiple RCA, SPDIF, and USB cables in the last two weeks. I will play the same songs for hours using different cables. It is amazing to see how each cable affects the sound. My next test will be with a few Power Cords.
So in summary, to answer your questions...Yes and Yes. Everything you do will help improve the sound. It might not be much but every detail counts. Enjoy the journey and when your wife asks you is this it...just smile at her and wink.