Audiophile's are famous for spending a lot of money on "snake oil" to get results that objectively cannot be heard and then claim the sound is better. Sometimes the sound is better, but the human ear cannot tell (lab equipment can). Of even the best lab equipment cannot find a difference.
Good enough if you are happy is good enough. Maybe you can do better in ways you can hear, but with "Flac is my source, decent DAC, decent cans" you are probably getting close to the edge of what the human ear can hear anyway (assuming good audio in that Flac, and the DAC/cans really are decent as you claim)
I recently got into making some sort of budget hifi setup, and found audiosciencereview.com quite helpful - a good amount of reviewed gadgets with focus on measurements. Ended up with kali lp-6v2 speakers and a SMSL SU-1 dac. Please don't tell me I screwed up. :-)
https://www.youtube.com/playlist?list=PL3A50BB9C34AB36B3
Highly recommended.
Almost all of these mind-bogglingly large numbers are built around recursion, like the Ackermann function, which effectively has an argument for the number of Knuth up arrows to use. Then you can start thinking about feeding the Ackermann function into that slot and enjoy the sense of vertigo at how insane that becomes.
I find it fascinating how quickly the machinery of specifying large numbers probes the limits of what's definable within the mathematical systems we use.
"Infinity is farther away than you thought."