With one of the key features of a Monk being their ability to use DEX as the ability scores to determine saves on regular unarmed strikes for a shove/prone/grapple condition, why is it with the Elemental attunement strike with an automatic shove based on STR save instead of DEX? If I wanted to talk to my DM about converting this into a DEX save like the other strikes are for this class, what would the formula be to make sure that it is scaled correctly?

I think you've gotten things mixed up a bit. For Elemental Attunement, the target rolls a Strength saving throw, but (per the base class's Monk's Focus feature) the DC for the saving throw is calculated using your Wisdom modifier, not Strength or Dexterity.

The DCs for saving throws you cause are always calculated as: 8 + your proficiency bonus + your relevant ability modifier. In this case the relevant ability is Wisdom. The fact that the target is rolling a Strength saving throw doesn't affect what ability you use to calculate the DC.

Awesome! Thanks for describing that to me. I was getting confused with the difference with the saving throw vs the shove or prone with the martial arts feature and with DnD beyond not adjusting them automatically for someone having a monk on their sheet. Just a lot going on and this is my first time playing this class on top of the new rule book so I appreciate the explanation. I will up my wisdom if I want that save to be higher than, got it!

Just to be clear, for a Monk, the saving throw DCs for unarmed strike grapple and shove options are calculated using your Dexterity modifier (per the level 1 feature Martial Arts). Any saving throws caused by something that you spend Focus Points on, including Elemental Attunement, are calculated using your Wisdom modifier unless otherwise specified (per the level 2 feature Monk's Focus).

I agree it's frustrating that the D&D Beyond character sheet doesn't show you those numbers on the Unarmed Strike description.

Yup that is now understood, that is why I was confused on with the same thing like shove I am using a different calculation but I suppose elemental attunement is more of a mental thing than just pure physical. Adding what I use Focus Points on too helps with understanding, I am "Focusing".

Quote from wagnarokkr >>

Just to be clear, for a Monk, the saving throw DCs for unarmed strike grapple and shove options are calculated using your Dexterity modifier (per the level 1 feature Martial Arts). Any saving throws caused by something that you spend Focus Points on, including Elemental Attunement, are calculated using your Wisdom modifier unless otherwise specified (per the level 2 feature Monk's Focus).

I agree it's frustrating that the D&D Beyond character sheet doesn't show you those numbers on the Unarmed Strike description.

Honestly, yeah. I wound up putting together a "How to Monk" cheat sheet to refer to when  playing my Elemental Monk, because there are so many different abilities using different Saving Throw attributes and DCs, as well as conditions I need to be familiar with.

So I can just rattle off, "Does an 18 Hit?  Cool, 11...Thunder Damage. Stunning Strike 14 CON?  Darn. Grappler Grapple 16 STR/DEX?  No? Okay, Elemental Push, 15 STR? Cool. Tavern Brawler 5' Push.  Attack Two..."