Warning: SPOILERS for Star Trek: Lower Decks season 2, episode 4 - "Mugato, Gumato".
The Ferengi are back in Star Trek: Lower Decks, but the opportunistic profiteers are more in line with Star Trek: The Next Generation's Ferengi instead of Quark (Armin Shimerman) and the Ferengi of Star Trek: Deep Space Nine. At the end of DS9, Quark's brother Rom (Max Grodenchik) succeeded Zek (Wallace Shawn) as the Grand Nagus of the Ferengi Alliance, while Quark himself successfully franchised Quark's Bar, but the Ferengi seen on Star Trek: Lower Decks don't reflect the changes Quark and Rom have made in the way their race conducts business in the galaxy.
The galaxy's ultimate capitalists, the greedy and profit-seeking Ferengi were introduced as villains in Star Trek: The Next Generation. However, it was Star Trek: Deep Space Nine that thoroughly explored the Ferengi and their culture, thanks to Quark, Rom, and Nog (Aron Eisenberg), who was the first Ferengi to join Starfleet. DS9 delved into the Ferengi Rules of Acquisition and introduced Grand Nagus Zek, along with Quark and Rom's Moogie (mother), Ishka (Cecily Adams). Other prominent Ferengi on DS9 included Quark's nemesis, Liquidator Brunt (Jeffrey Combs), his weapons-dealing cousin Gaila (Josh Pais), and the dangerous Leck (Hamilton Camp). Ferengi episodes were comedic highlights of DS9, especially "Little Green Men," where Quark, Rom, and Nog ended up being the aliens who landed in Roswell, New Mexico, in the 1950s, and "The Magnificent Ferengi," when Quark led a ragtag group of Ferengi to rescue Moogie from the Jem'Hadar.
However, the Ferengi who popped up in Star Trek: Lower Decks season 2, episode 4, "Mugato, Gumato," were more in line with the Ferengi seen in the TNG season 1 episode, "The Last Outpost" than Quark and DS9's Ferengi. Lower Decks' Ferengi marauders are energy whip-cracking profiteers who were illicitly harvesting families of Mugato on the planet Freylon IV. The Ferengi even had no issues kidnapping Ensign Beckett Mariner (Tawny Newsome) and the resurrected Lt. Shaxs (Fred Tatasciore) of the USS Cerritos. Thankfully, Ensigns Brad Boimler (Jack Quaid) and Sam Rutherford (Eugene Cordero) negotiated their fellow Starfleet Officers' release and convinced the Ferengi that it would be more profitable for them to open a nature preserve for the Mugato that would be open to then public.
When Mariner asked the Ferengi if they've heard of Quark, their marauders' leader angrily replied, "Of course I've heard of Quark!" But these Ferengi don't seem to hold Grand Nagus Rom's brother in high regard. Quark didn't have a great reputation among the Ferengi since he worked so closely with the United Federation of Planets on Deep Space Nine. Worse, Quark's nephew Nog joined Starfleet, and Rom likely continued Moogie's controversial reforms that overhauled Ferengi society as Grand Nagus. Considering how powerful Quark's family became by the end of DS9, it's understandable if there's resentment among other Ferengi entrepreneurs who are seeking profit in the galaxy.
Meanwhile, Quark has seemingly found success after DS9 ended, even though he and the rest of the cast have yet to appear in the new Star Trek series on Paramount+. Star Trek: Lower Decks showed that Quark, along with Vic Fontaine (James Darren), has franchised on other planets. Star Trek: Lower Decks is set about 5-6 years after DS9 ended so Quark has been able to franchise his tavern successfully in that time. Star Trek: Picard season 1, which is set about 19 years after Star Trek: Lower Decks, showed that Quark's Bar is also on the planet Freecloud. No doubt, Quark's growing business benefited from his brother Rom becoming Grand Nagus, although it's not clear whether Rom is still the head of the Ferengi by Star Trek: Lower Decks' time.
Quark deeply wanted the respect of other Ferengi on DS9 but considering how envious the Ferengi typically are, it's likely that most Ferengi now resent how successful and famous Quark has become. Quark, Rom, and Nog are seen as practically "hu-mons" by other Ferengi so marauders wouldn't want to emulate their business practices, even if they covet Quark's profits. Unfortunately, Quark's absence from Star Trek: Lower Decks continues how Star Trek: Deep Space Nine still isn't being integrated into Star Trek on Paramount+ like Star Trek: Voyager is.
Star Trek: Lower Decks streams Thursdays on Paramount+.