For my first child, I bought a bigger cot (130x70cm) that grows with the child (convertible type) because it can last her for 6 years (that’s when I plan to get her a bed). For my second child, I got the standard size (120x60cm) because she can inherit the other cot next time. I think the baby sleeping in the cot is all about sleep training. I trained my first child to sleep in the cot and in her own room since she was a baby, so she has no issues. If you start with co-sleeping, then of course baby may not want to sleep in the cot later on. I think as long as the cot is safe and there’s a good mattress, then the preference for the brand/size is dependent on you, not baby:)
You may want to buy a playpen instead
Cherlyn