I'm not a big believer in tweaks but somebody recommended the ifi iPurifier3 to me and since it was only $129 on Amazon with free returns I bought it. I hear a subtle, but very real, improvement using it on both of my systems. It makes no sense to me and maybe it is simply confirmation bias but I have listened repeatedly with it in and out of the system and it makes a positive, albeit difficult to describe, difference. I also bought an Audioquest Jitterbug for $69 which makes a positive but less dramatic difference. I think the iPurifier3 is worth the extra $60. Try it and return it if you don't like it.
Also, I got the World Wide Cables 12' RCA cable to replace a more generic RCA cable. I didn't A/B test that and I made another change in my system at the same time but I think it made a small positive difference. Emphasis on small.
https://www.amazon.com/gp/product/B07FQPB33NAnd if you decide to try springs these are the best
https://www.amazon.com/gp/product/B08MPVFVRS/