Congratulations on achieving so much, for so little.
A free tweak is to try soft cotton packing strings as slings to lift up your cables and interconnects from surfaces. The string can be held up, in turn, by attaching to your nearby window shade cords.
Often, there is an improvement in clarity, and easy to quickly verify if any improvement audible, in your own system.
It is great to see that giving careful thought to what we purchase can achieve more than merely opening wider our wallets.