I've struggled with the same issue. The keys, as I've learned them, is to a) get to a place where you can invest up front in reducing your cost of living in the medium-long term, b) run like hell from the hedonic treadmill of trying to keep up with your peers' poor financial decisions, c) look carefully at what parts of your "decent lifestyle" make you truly happier, which parts are performative, and for which parts you can replace spending with effort without a loss of quality (for example, you can learn to cook very nice food, at a much higher quality than you will get at a restaurant for much less money; there's also no better feeling than feeding your friends).
Keep in mind that the lifestyle changes you make now pay off more than double, by helping you save faster, by having those savings accumulate interest/earn you money, and by reducing the amount of money you need to sustain retirement indefinitely.
Finally, make compounding growth your friend, not your enemy. Kill debt ASAP, and start socking away as much of your money as you can in a growth-bearing account. If you can reliably save 50% of your income in an account that beats inflation by 4%, you can support your lifestyle indefinitely on growth after 17 years.