The potluck is one of the best formats for feeding a crowd. It spreads the cost and effort, it gives everyone a small stake in the night, and it usually produces more food than any single host would have made. It also has a famous failure mode: everyone brings the easy thing, and you end up with four bags of crisps, three bottles of wine, and no actual dinner.
Name the gaps, not the rules
The fix is not a rigid assignment system where you tell each person exactly what to make. People resent that, and someone always forgets their slot. The fix is to make the gaps visible. Say what is already covered and what is missing, and let people claim the gaps themselves. "We have plenty of drinks and snacks sorted, still need a couple of mains and something sweet" gives people a useful nudge without bossing them around.
Use a shared bring list
When you set up the event, add a things to bring list with the categories you actually need: a main, a salad, a dessert, ice. Guests can see what is on it and what others have already claimed, so the second person to look does not duplicate the first. This is the part the group chat is bad at. In a chat, the offer to bring a lasagne scrolls away and three people make pasta. On the event page it stays put.
Cover the boring essentials yourself
As host, take the unglamorous items off the list before anyone else can pick the fun ones. Ice, cups, plates, bin bags, somewhere to put coats. Nobody volunteers for ice, and a potluck with no cups is a problem at 7pm on a Friday. Handle the infrastructure and let your guests bring the food they are excited to make.
Plan for the no shows in the kitchen
Some portion of any guest list does not turn up, and a couple of dishes will not arrive. Do not plan a menu that collapses if one main goes missing. Keep something simple in your own cupboard that can stretch the meal if needed: pasta, rice, bread, eggs. You will rarely need it, but knowing it is there means you are not anxious when someone texts an hour before to say they cannot make it after all.
The point of a potluck
A potluck is not really about optimising the menu. It is about everyone arriving with something they wanted to share. The coordination only exists to stop the easy failure modes so the good part can happen. Name the gaps, keep a list, cover the basics, and let the rest be a happy surprise.