I've been googling on 0DTE. Basically they're about trading the SPX and XSP (mini) options on the CBOE. Just trade it on the day of expiration. They european style so no worries about exercise.
I found this video about a lady doing 0DTE iron condors using index options (I found it fascinating):
0 DTE SPX MEIC Strategy - January 16, 2023 by Tammy Chambless - YouTube
I've been doing it in the form of Event Contracts for several months now and there is a lottery-like feeling to it. For example if you watch it as it approaches expiration, something can move from 25 cents to $20 dollars in very short time.