You could just go for normal full fat greek yoghurt rather than natural greek style it's a lot creamier and thicker
We give Oatly oat based yogurt due to her milk allergy, I give my toddler regular greek yogurt and the fake stuff is a lot more thick/ creamy. Tastes horrible imo but she doesn’t mind 😅
Any yoghurt except natural is full of sugar but no worse than baby pouches if it's the no added sugar ones. If he eats it why change? Add fresh fruit for different flavours or cereal. My lo has porridge with banana, rasberries or blueberries for pudding. I occasionally give him a no added sugar munch bunch which is probably the least sugary
We use glenilen natural yoghurt it's from cork and it comes in a 'kids' pouch with no added sugar as well we can get it in the north of Ireland unsure about Britain
I use Yeo Valley natural yoghurt and he loves it. Can buy their big 950g pots too so it lasts a little while (I eat it too!)
Not sure if you’d use this as an option but my baby has soya alpro yoghurt due to her milk allergy & she loves it x