Two possible strategies:
1. change the conditions to make it harder for grubs to survive,
2. support the development of a population of grub eaters.
If moisture in the soil is making life easier on the grubs, one thing to consider is raising the level of the beds where you are losing too many plants to grubs. What do I mean by "too many"? Well at a low level population, you lose a plant here and there, and what you get in return is a population of creatures who eat grubs, and once they get established, then they keep the grub population in check.
If the cicadas are
native to the area, there are cicada larva eaters. Figure out who they are and which would be easiest to host in your garden space.
Here in the desert, with gravity flow irrigation, because there is no rain during key parts of the year, I do the opposite. I plant the plants lower in the soil, so they can have their roots down in the layer where life is happening in abundance. I keep the top layer of the soil dry, there is less evaporation from the surface of the soil and because of the dryer conditions I have fewer aphids, no slugs no snails. Just an example of making adverse growing conditions to discourage creatures that are not contributing to my goals.
With regard to populations of predatory creatures, it does take awhile for things to stabilize. I've had a grasshopper problem for several years. Grasshoppers are migratory, so even if all today's resident grasshoppers were gone today, there would be more tomorrow. To make matters more challenging grasshoppers are affected by temperature and level of moisture in the winter and spring, and I never can remember which particular combination gets the plague levels, but the grasshoppers take care of that. They come when conditions are right for them. I used to keep guinea fowl, and they kept the grasshopper population down, and they ate more of other insects and more bought
feed when there weren't so many grasshoppers. I had to get rid of the guineas, and the grasshoppers had another population explosion. This year I had thousands of "hatchling" toads. I think they were feeding on the tiny grasshoppers. Next year with so many toads, I think the grasshoppers will have a hard time reaching plague levels. They have to go through several very tiny instars, just right for new hatchling toads, and small toads, and as the season progresses, the toads will be bigger, able to eat the larger grasshoppers resident and incoming. The way I imagine it, I'm raising an army of grasshopper eaters. As long as the grasshoppers are more numerous than the toads can keep up with I think my population of toads will increase. When I have the two populations at levels that balance, the numbers of grasshoppers should level out. And the toads will not grow as fast, maybe the newly hatched ones will not survive at the same rate.
One predator one prey is over simplified. Ideally there would be more than one food species for the predator, and there would be more than one predator on the pest. The increase of complexity will create a more stable system, but it's easier to explain in terms of just one.
I don't know how well I did at explaining, but I hope you get the point, and that finding the predator species will not be too difficult.
With fall coming on, you'll have all winter to study and research, and hopefully when spring comes around and the soil warms up, you'll be ready! You might have so many different things you want to try that you'll be looking forward to those grubs, so you can test all your ideas.