This was my personal big breakthrough. I realized that humans deal with abstractions of things and not things themselves. Accordingly, most of what humans argue about isn’t even real, but rather only what is perceived through layer upon layer of abstraction.

I've had this revelation too but wouldn't describe it as a big breakthrough though sometimes it feels like it should matter more. Can I ask how you feel like this affects your day to day life?

It allows me to turn the volume down on things. So many things actually matter very little. Also, it allowed me to see things a bit more clearly. For example, all forms of categorization and measurement are somewhat arbitrary (no matter how useful). Another one I got from this is that meaning is assigned and not found as it exists only in the mind. Or, another favorite of mine, concepts don’t really exist. Like meaning or measurement, they are useful but not real.

For me the most concrete practical use of this kind of thinking is achieving "mind over matter" when dealing with physical pain. It seems to ease the emotional impact if you focus on the physical sensation of pain itself rather than the idea of pain, which carries so much more baggage that adds an extra dimension to the suffering that becomes counterproductive in non-survival scenarios like lifting heavy weight at the gym.

Indeed, except conceptually, there is no actual separation between "things."

See: quantum mechanics.