How do I make big maps for top down open world games?

A question that has been asked 100 times before...I know as I have read all the threads asking this question.

But there doesn't seem to be a consistent answer to this question (more than 1 way to skin a cat I guess)

So I guess my question is, what is the best way to make a large map (51200,51200)

Using Tilemap for the roads, paths, grass etc... I'm using 3d object for the buildings, cars are 2d sprites, people will also be 2d sprites

Should I load it all in chunks, or have 1 big Tilemap and the buildings load in chunks, or just have at it and have everything in 1 big map and hope it works?

Picture the original GTA as a reference to what I want to build (I'm not making a GTA clone but I want a map that's like it, with cities and out of town areas etc...)

I've started 1 big map, but in the editor it feels like it starts to lag when I'm editing stuff, so I started to think about chunk loading, but not sure if it will make any difference as then it's just using resources to load/destroy objects.

Any help would be greatly appreciated.

Thanks <3

dop2000 thanks for replying mate, I thought this might have been the case.

I've not used hierarchy's before (not actually noticed it tbh)

But from a min of playing around this looks promising thanks.

dop2000 Ok so hierarchy seem like a perfect fit for what I'm trying to do,

My one problem is that when i spawn a new chunk in use hierarchy the tilemap and objects are all on the same layer, now i know i could do an event saying on x created move to layer, but just wanted to check that I'm not missing an option somewhere that stores the layer from when i add the object to hierarchy?

check that I'm not missing an option somewhere that stores the layer from when i add the object to hierarchy?

I believe there is no such option..