I am in Southern California and most of my yard is succulents. These plants need very little water and too much causes root rot. There is no setting on Rachio for succulents that I can find. On our prior system we would typically not water them at all during winter months, due to a combination of occasional rain and their lack of need when it is not hot, then in summer maybe once every couple of weeks.
It looks like an option would be to set the Allowed Depletion to very high (e.g. 100%), but I’m not clear if that would result in longer gaps in watering. Perhaps there are better adjustments.