i have a Li, a Sherwood , a Coco and another un-named (not Lang)
and my Li produced a couple in Spring, and is just starting to flower again.
As far as water...
i think Juju is a lot more drought tolerant than most people think.
Or, there is some misleading info out there.
Last year, we went 2 months in the Summer with less than 1/2 inch of rain.
i think i misted the leaves and mulch layer a couple of times
but, certainly did not deep-water it.
it had no problem fruiting and holding on to the fruit.
it was fairly new and small, so there was not a lot, but ,
lack of water did not seem to effect it.
Ziziphus — a Multipurpose Fruit Tree for Arid Regions
Abstract. The progressive desertification in many semiarid regions of the world
increases the need for plants that can cope with arid environments and meet
peoples' requirements for food, fodder and fuel. Species of fruit trees in the genus
Ziziphus represent examples of such mUltipurpose plants with great potential for
selection and use in drought-prone regions.
https://link.springer.com/chapter/10.1007/978-3-642-59560-8_41CFRG
Irrigation: One of the outstanding qualities of the jujube tree are its tolerance of drought conditions. Regular watering, though, is important to assure a quality fruit crop.
https://www.crfg.org/pubs/ff/jujube.html