The Egypt international - who shares a dressing room with Reds star Mohamed Salah on national team duty - is reported to be dreaming of a move to the Premier League after waxing lyrical about Salah earlier this year.
The striker's existing connection with the 32-year-old has naturally fuelled suggestions that he could end up at Anfield, as has his terrific record of 14 goals and 10 assists from 16 matches in the 2024-25 season.
It was claimed earlier this month that the Merseyside giants had stepped up their interest in signing Marmoush, as Arsenal and Bayern Munich are also rumoured to be lurking with intent.
Frankfurt sporting director Markus Krosche has sent a firm warning to Liverpool over their chances of signing Marmoush, though, claiming that a €40m (£33.4m) package will not suffice.
Liverpool to pay higher fee for Marmoush than Salah?
When that price tag was put to him in an interview with WELT, Krosche replied: "That won't be enough,", although he did not close the door on Marmoush jumping ship in the future.
"With many players who come to us, it is ultimately the case that we offer them an environment in which they can develop - knowing full well that we will let them go if they develop faster than the club itself," the Frankfurt chief added.
"This is an agreement we make with the boys. That's why we are able to attract so many exciting players, because they know they can take the next step in Frankfurt.
"For Omar, it's not part of his everyday life. An important indicator is a player's performance. And he performs well in training and, not least, in matches."
Twenty-five-year-old Marmoush still has three years left to run on his Die Adler deal and boasts an eye-catching tally of 31 goals and 16 assists from 57 appearances for his current club across all tournaments.
Should Liverpool be prioritising a move for Marmoush?
If Liverpool are to pursue a deal for Marmoush next summer, they can expect to be quoted around £40m to £50m for the 25-year-old, which would trump the £34.3m that they paid for Salah's signature in 2017.
One look at Marmoush's phenomenal record in 2024-25 suggests that he is ready for Premier League football, but the centre-forward position is arguably the one area that Liverpool have no need to worry about at present.
Diogo Jota and Darwin Nunez are both competent options up front, Cody Gakpo is also capable of filling in centrally, while Luis Diaz scored a hat-trick through the middle against Bayer Leverkusen in the Champions League.
For now, all efforts must be focused on Salah, Virgil van Dijk and Trent Alexander-Arnold's contract situations, as well as how to go about replacing any member of the trio should they depart.
Even if Liverpool are successful in keeping all three, the left-back, centre-back and defensive midfield positions are surely more pressing matters for Arne Slot rather than a new number nine.