How to Make many pizzas for large party?
Yes, preparing discs of dough ahead of time, separated by parchment, wax paper or clingfilm does work. The biggest risk is that the dough tends to dry out a bit, so keeping the whole mass wrapped up in clingfilm and possibly in wide closable containers may be worthwhile.

I don't know how long it would take you to pre-portion 20 pizza doughs; I'm not super-efficient on that yet so it would probably take me a good solid hour. That might be short enough so as not to require additional retardation.

Most pizza joints at least pre-portion the balls of dough, and they let them relax at (oven-) room temperature, so that they're easy to stretch.

If this is a casual party with friends, rather than a formal dinner or a catering gig, though, you may consider involving your friends to do the work; they may appreciate the social aspect of throwing/rolling dough together (depending on your technique preference), and even topping the pizzas themselves, with your guidance. You may want to make a bit of extra dough to accommodate errors.

I've actually been to an event where everyone brought their own preferred dough recipe to test it out on a wood fired oven, which was a leisurely several-hour event with many successes and a few "failures" (or lessons learned; brioche dough doesn't love 700F ovens). We all just grabbed space on the bench when it was practical, and queued up for the oven when practical.

An alternate strategy is to have plenty of dishes out on the table that aren't time and temperature sensitive, and let people nibble casually while you prep. Marinated vegetables, cold cuts, cheeses, bean dishes, etc. Then spend time chatting with each person you're making pizzas for while you prep them, maybe three or four at a time, to tweak to their preferences and whims.