You want to keep it raw, and without additives? You could use rennet, that would help stabilize the lactic gel. But the problem you run into then, even with high solids in the milk, is it will have whey on top of the creamline. It can work if you use a really tiny amount, just enough to stabilize the lactic curd. There are a few vegetarian rennets that can withstand the heat. What do you use now? Mucor-based?
I tend to prefer a 3-pronged approach, similar to commercial manufacturers (who actually use more like a 5-prong approach). One, I like using a culture that will give me an extremely thick set. Two, I like to add a small amount of something better mouthfeel and stability to prevent the lactic gel from separating. Usually, this is carageenan that I make from irish moss (just boil the moss, it makes natural carageenan). And three, I add something to help retain water. This is often agar, and at times rennet.
This is when the milk is thin. Much of the time, solids are so high for me, I get a thick set with only culture.
Another option you could try is to make a hybrid product. Preculture with LM from danisco until pH drops to ~6.0, then add in a starter slurry that has the usual thermo mix, and heat to thermo temps. You will get a better set that way by using the chaining properties of LM. In this approach, flavor will be more buttery.