Hi, Just short Question, , could you please recommend some substitute to the pork, maybe eggplant? Or another veggie, thank you

Although a relatively small amount is called for, the pork here adds flavor, texture, and fat. I would go with both 702551's suggestion to use rehydrated dried shitake mushrooms, and Nancy's idea to use portabello mushrooms, cooked down. Those will help provide the chewy texture you're missing. I'd also add extra fat to replace the considerable amount even 3 ounces of pork releases. In this case, I'd add at least another teaspoon of sesame oil. I would not worry about its flavor overwhelming the dish, given the other bold flavors in the ingredient list. ;o)

It's only 3 ounces of pork, a small amount.

I wouldn't bother seeking out a replacement ingredient to purchase. I'd just use whatever I have in the fridge that I fancy or even just omit it. It's not like the sauce will fall apart without pork.

I suppose a couple of rehydrated shiitake mushroom caps (chopped up) would add a similar texture as the cooked ground pork, plus add a little umami. I'd probably do that since I always have some dried mushrooms in the cupboard.

In addition to Nancy’s suggestions, I think you could also substitute cracked wheat (as in tabouli), couscous, or quinoa that you’ve pre-cooked in a flavorful broth.

Sounds like you need some vegetable that could be a solid base for the sauce. In addition to the eggplant you suggest, consider:
cauliflower steak
carrots
cabbage steak (1" or so wide slice from the head of a cabbage)
squash or sweet potato
mushrooms, especially portobello caps.
Each would need to be roasted to remove water and increase flavor before adding to the dish.