This design argument is pretty low iq tbh. My fucking christian family tortures me with that shit.
We are observing it from the post-creation perspective which is why it seems that its designed to us, because everything is so perfect. But in fact, it's not perfect at all, the whole premise of our existence is chasing the sun of perfection.
Larp this nerd shit for a moment. Say you have a dice. You roll the dice 6 times and acquire 6 random numbers. Then you use those numbers to construct your DND dungeon character. There will be 6 questions u just answer using the 6 numbers you rolled. Like your background story, your class, your attributes, etc...
Now, if you were ever to change even 1 of this attributes past the creation stage. Your character would no longer be the same. It's the same for universe. It's just a seed, like in a minecraft.
If our universe was drastically different, for example if we only could exist on a 2D plane then it would seem perfectly normal to us and everybody would say the same shit that it was designed coz its too perfect. We are the product of the universe not its design. We reflect the state its in not the other way around.