Agree with the other posters here. If the recording is damaged at the source—badly compressed recording—there isn’t a fix. The irony, as the OP is discovering, is that as the rest of the system improves, the defects in the recording become more obvious. I recommend listening to the badly compressed stuff with a $50 Bluetooth speaker because it hides more of the warts and you may enjoy it more
A DAC to help overcome compressed music?
I have found after upgrading my system, to a much higher level then I ever had before, that with some of the music I enjoy I can now really hear how compressed the music is. I could always tell, but now it’s really obvious to the point of wondering what I can do about it - from a digital source perspective. Would perhaps a certain type of DAC or DAC’s that have various different settings as some do, help “improve” the compression in some way? Or do I simply need to live with it? I am sure there are many others that have had this happen to them. I use a Bluesound or Qobuz currently.