Quark is more of an inside track informant than an outright villain. While he often held to the Rules of Acquisition, he found himself going against the grain enough to be exiled.
I always thought of Quark as the moral center of DS9. Hear me out. It's a darker show, much more shades of grey, a bit of a break from Roddenbury's vision of star trek. Instead of Jean Luc's pompous speeches, and Janeway's infuriating (and inconsistent) adherence to the prime directive, DS9 actually toes the line and crosses it many times. Quark meanwhile has his own code, and he sticks to it as faithfully as anyone can. He is true to himself and his species and pretty much never crosses his own line - he crosses our line for sure, but rarely if ever his own. Pretty much the only time I can remember him doing something un-ferengi is when he turned down a gazillion bars of latinum to run weapons for those people planning on blowing up a planet with a few million people on it. At the end of the day you can always count on quark doing the right thing. He's quite complex, and by far one of my favorite characters in all of Trek.
I liked the purity of quarks character. Always after whatever provided the most opportunity and profit. He frequently was thwarted in his shady dealings in the pursuit of profit, but that's capitalism baby!
Not to imply I'm a fan of capitalism, far from it, but he was portrayed so perfectly as the embodiment of pure, unfettered capitalism. Regulations were little more than a suggestion and if breaking them didn't result in a loss (of profits), or if it had a fairly low chance of affecting his profits, in his mind, then he would simply ignore rules and do whatever the hell he wanted.
Looking at the world today, that's exactly what capitalism is doing. If you have laws but no enforcement, corpos will do it because the punishment is basically non-existent. If you have laws and enforcement, but they can hide/relocate/obfuscate that they've broken any of those laws, then they'll do whatever they damn well please, and just hide it. If the punishment for the infraction is less than the profit to be made by ignoring the laws, they'll do that too.
One notable example I like to go back to frequently is relating to tobacco. The laws are there but enforcement is stretched so thin that the chances that you'll be caught are pretty minimal. So many places, like corner stores and gas stations, don't give enough of a shit to enforce the laws. They make so much from just selling to whomever asks regardless of how old they look and whether they have ID or not (within reason, I don't think anyone is selling to 10 year olds), they'll just do it anyways. When/if they catch a fine for it, they'll easily pay for it with all the profit made from not giving a shit about identifying people. As long as you look old enough, or choose enough to old enough, you can buy some. I'll strongly express that not every place is like this, but there's a nontrivial number that are.
If you take that same approach with everything, you get corpos just eating EPA fines for polluting that are a fraction of what they would need to spend to properly dispose of their industrial waste. There's probably thousands of examples, but I won't waste everyone's time to dig them up and cite them.
He was the perfect embodiment of this profit-first mentality. Easily one of the best ferengis in any of the trek universe.
Good news! If the MAGA party wins in November they'll surely defund, gut, or do away with the EPA entirely, so pollution fines will drop to zero, clearly indicating pollution is gone!