How should I divide an open world map?

So I've been searching all over the internet about open-world maps in Unity and I've found a lot of answers, many different. A lot of them are old, so I wanted to ask here what's the best method.

These are 2 methods I've heard of so far:

1. Dividing the map into multiple scenes and loading them as the player gets closer

2. Dividing the map into tiles and putting them in a game object and just enabling and disabling them as I need them

Which one of these 2 methods is the most performant? Is less memory used when the map is dividing into scenes or if it is divided into tiles in one scene?

Side question: If the 2nd method is also good, why do I need to divide the map into tiles at all? Can I not just use LODs and culling so that objects further away do not get rendered?

Thanks in advance!