Ok so Dhampir gets 

Deathless Nature

You don’t need to breathe.

While Reborn get

Deathless Nature

You have escaped death, a fact represented by the following benefits:

• You have advantage on saving throws against disease and being poisoned, and you have resistance to poison damage.
• You have advantage on death saving throws.
• You don’t need to eat, drink, or breathe.
• You don’t need to sleep, and magic can’t put you to sleep. You can finish a long rest in 4 hours if you spend those hours in an inactive, motionless state, during which you retain consciousness.  

So why does Reborn get so much more for an ability that is named the same thing vs Dhampir just getting hey you don't need to breathe,  I get eating as goes hand n hand with vampire trait, but why do Reborn get warforged plus deathsave as opposed to just being well warforged.

Because they’re different lineages and they’re balanced differently? Not sure I understand the question.

It is unfortunate that they gave them the same name, however...

.Yeah it's basically why did they give it the same name but be completely different abilities.

That is unfortunate.  Something of an editing failure in the book, methinks.  Imagine it will be errata'd eventually.  I understand it, though - 'Deathless Nature' is a very evocative name, the sort of thing a player would be excited to be able to write down on their sheet.  "Breathless" just doesn't have the same zing.

Different race different balancing; simple. Admittedly it's a bit misleading that they called it the same yet the reason should be obvious. The Dhampir is strong enough as is. Giving him everything the Reborn gets with this feature on top just because the feature is named the same would break the balancing.

It is unfortunate that they gave Dhampir and Reborn the same named feature, but it’s not the first time. 

Monks and Barbarians have Unarmored Defense, but they are different. Similar but different. 

Whisper Bards and Soulknife Rogues both have Psychic Blades, but they are different too. Quite a bit different.

Guess they weren’t paying attention when they names these things. 

Quote from ThriKreenWarrior >>

It is unfortunate that they gave Dhampir and Reborn the same named feature, but it’s not the first time. 

Monks and Barbarians have Unarmored Defense, but they are different. Similar but different. 

Whisper Bards and Soulknife Rogues both have Psychic Blades, but they are different too. Quite a bit different.

Guess they weren’t paying attention when they names these things. 

 Like in your examples they are similar but Dhampirs get 5 extra feet of movement, Darkvision, the bite attack that can do some healing and lets not forget they can wall crawl like spiderman. Reborn were dead now they aren't I see them very well balanced even with the similar ability names.

But what is the purpose for not needing to breathe if literally every situation except being under water or suffocating makes that ability pointless?

Quote from FalconWolf >>

But what is the purpose for not needing to breathe if literally every situation except being under water or suffocating makes that ability pointless?

 

 Stinking Cloud

things like this specifically call out creatures that can’t breathe. Not common but stuff like this is out there

Wish they gave the Dhampir Resistance or Immunity to poison.