As I read through this I’ve kind of gone in the direction that @hilde45 makes above. I look at the “investment” in audio equipment as being nothing more than investing in my own enjoyment (or myself).
Knowing that there is always something better out there is a struggle that some deal with better than others but I think once you get to a certain level of experience you’re more able to appreciate what you have and make better decisions about what’s important rather than placing that importance on having the next best thing.
I don’t know if I would say that I’m finished when it comes to acquiring gear but when I sit down to listen the last thing I’m thinking about is “would be better had I spent more money?”. Be happy and enjoy your system for the experience it offers you and if you feel that experience should be heightened go for it- there’s nothing wrong with that either!