Hi Victoria
In our commercial stores here, the succulents are mostly in a filtered but bright light area, there is screen to help provide shade to the plants during the hottest part of the day. As succulent as they are holding water in their leaves or stems, they also burn when intensity of light is too much. Usually I see them being deep watered heavily at least once a week.
In my garden, I do similarly, potted in very well draining soil, shallow containers with drain holes, and I water them once or twice a month. But have to adjust when our forecasts are intense dry and triple digit hot, I may step up watering mid-week.
Succulents have varying growth habits, some being desert-types, alpine, or tropical types. So the desert types really wants very dry conditions with full sun, so most cacti falls in that category, the alpine and tropical types are okay part sun-part shade. Some succulents go semi-dormant in intense heat days, so it is understandable if they seem to slow down in growth. They resume active growth again when temps cool down in the mid 70's to low 80's.
Stomates of succulent leaves are closed during the day, so they ably save their water. So if you can direct watering more directly at soil level and do watering early part of the day, that way, the leaves and roots can dry out properly and not invite fungal rotting. I would not go dunk watering either, just water thoroughly at least once a week and let it dry out. It would help if you water with a long nozzle sprayer so you can easily direct/spray the water directly to the root zone area.
