Fallout 4 DLC question?

If I buy a Fallout DLC, is it then integrated into the normal map, or is it then like a level, which has nothing to do with the normal game plot / map (PS4). It is also advisable to buy the dlcs at the beginning of the game or only after you have played it through.

The DLC's are integrated into the game world / game story.

Ideally, you start a new game after the DLCs are installed.

Automatron and Vault-Tec Workshop act in the Commonwealth, Nuka-World and Far Harbor are each a map extension. Sometimes there are cross-connections to the main quests.

The 2 DLCs Far Harbor and Nuka World are separate worlds that must first be discovered and then entered by fast travel. You are therefore not directly connected to the Commonwealth of Nations. You can only enter it when you reach a certain level. Since you don't necessarily have to go to story in Fallout 4, like for example you don't have to save Preston and get to know him first, but you can go straight to diamond city. Also helpful in this example, because if you already have something to do with preston and go to nuka world and join someone (so as not to spoil a lot here) you will problematically turn Preston against you. If you don't join them and kill them, or you do that with nuka World first before you rescue Preston, he won't get mad at you.

The other DLCs such as this one with the robots and the vault are also optional and this time are only in the Commonwealth. You can complete it at any time as soon as you have reached the required level to unlock the quests.

Ps I have all the DLCs and have the game through with all successes (xbox).

I recommend a few more creation club content in case you need a little more specialized firepower. The CC items are mods that are affordable for real money, but since they are practically integrated in the game, you can still unlock trophies and successes with these CC mods - in contrast to the mods published by users.

As items I recommend: X02 Power Armor of the Enclave, the Chinese camouflage suit, the Tesla cannon, and the anti-tank rifle.

And yes, I know the CC is hated. I only get the items that are 100% discounted and the items that I had a lot of fun with in Fallout 3.