I do not own a car, I do not fly, I buy clothes used or new just once a year. My newest smartphone I bought five years ago (and I just bought a new battery for $10, so I can use it for five more years). My utility company stats says my energy consumption is overall very low. I eat meat once a month. I try to own as few things as possible. I try to write and deploy code in energy efficient languages (Go, Rust, C, ...) [1]. I self host some services on my arm board that consumes 0.79W when idle.
I do not feel, that it makes a large dent, but I feel that I'm way ahead what the average person does in order to reduce their environmental footprint.
Also, I do not feel I'm cutting myself short and I still depend on many of the niceties of modern civilization - but, I'd also be happier, if my footprint would be even lower.
[1] https://greenlab.di.uminho.pt/wp-content/uploads/2017/10/sle...