How long do you try the different things? I think you’d need to be eating like that for at least a month to really start to see a difference - it’s not instant.
I felt like you did and I’ve lost 2 stone now. I have two ‘proper’ meals and for my tea, half my plate is veg. I drastically cut my portion sizes of pasta etc and try and eat lots of protein.
So for me I might have porridge with protein powder in it and strawberries, chicken sausages with eggs, scrambled egg on brown toast. I have this around 11am. Then 3ish I’ll have some tomatoes, cucumber, cheese, or sometimes a protein milkshake (I like the Ufit ones).
Then for tea I’ll have a small portion of something and half my plate veg. Yesterday I had pasta bake and my ‘slice’ was a small square of it, with broccoli. I made the sauce from scratch using lots of veg as jaw sauces are sugary.
Other teas I have are chicken with veg, meatballs in like a marinara bake type thing (no pasta or anything), pizzas made using one wholemeal pitta bread with veg and sweet potato air fries, omelette with veg.
I had to totally change my diet, reduce the carbs and my portions. I also get 10k steps a day even WFH most days by going for a walk at lunch and after work.
The thing with cereal is that unless you’re weighing it out, there’s no way you’re eating the recommended portion, as 30g is just absolutely nothing. I’d rather eat porridge because I’ll be full.