I'm somewhat local to this case, and I think about it a lot. Ultimately I have two theories, and I've done multiple deepdives on the case as it doesn't seem to make much sense at all.
Theory one is suicide. Being near the coast there are a large amount of suicides by drowning, with many being reported missing as their body will likely not be found. One off the top of my head is Owen Harding, last seen on Beachy Head during COVID and not seen again. Beachy head is a common place for those struggling to take their own lives, unfortunately. Georgina was anxious and bulemic, as well as being prone to drinking (
Disappearance of Georgina Gharsallah - Wikipedia), so I don't think it's out of the relam of possibility that she may have been struggling to the point of suicide. One thing I can't fathom about this is how she was not seen on CCTV: I tried to research cameras nearby the shoreline in Worthing at that time, but didn't have much luck.
Second theory is foul play, specifically related to drugs. It's pretty well known in Brighton that there's a large drug scene, many of those involved being Albanian. Such gangs have been pretty violent historically, for example Altin Molita who was stabbed by a so-called "murder gang," and another man being fatally shot over a dispute between two Albanian families in Hove. I don't want to make any assumptions, but given Georgina's last job in a kebab shop which was "used as a front by an Albanian crime family. This family reportedly supplied
Class A drugs in the Brighton and Worthing area. The family gang enjoyed a reputation for violence. Gharsallah appeared to be well-acquainted with members of this family. The father of her two children had also worked in the kebab shop," it doesnt seem out of the question that this relationship could have gone south. IMO there's a good chance that a struggling mother may have made a difficult decision and a subsequent mistake.
I could be completely wrong, and I'm speaking from my own experience only. There's a decent docuentary on Channel 4 about her disappearance, for those based in the UK, I'll try to find it now. JMO