Dragon's Wrath Weapon still not fixed after 5 years.

The Dragon's Wrath Weapon can still only be added to a character sheet as a Longsword and -unless I'm blind- doesn't show the breath attack from the Wakened and Ascendant variants. I doubt this will ever be fixed but posting this is worth a shot.

You are correct but there's explanations for these.

The Dragon's Wrath magic item can be any type of weapon. There's 37 weapon types, not including more exotic stuff like guns. There's 4 versions of the Magic Item to represent the item's "state". That means the devs would need to make 148 entries. Given that you can just make a copy and change the weapon type within a minute (less if you're familiar with it) and would only need to do that maximum of 4 times for your character (usually less, though). It doesn't seem worth it for the devs to clog up the inventory system with so many nigh-identical entries. 

The magic item system is limited: it cannot add extra damage that can be rolled and it cannot add actions to the sheet (beyond the normal weapon attack). This may change as the platform upon which D&D Beyond is being changed so it may develop the support for these features in future. 

So for now to get these weapons working properly you need to homebrew. 

For the dragon breath you are best making a copy of fireball spell, changing the area type and range to the cone, and adding upscaling for 7th level to change the cone size. Also change the damage type to the one your weapon will be. Then add the spell to the weapon at the relevant level (3rd for 8d6 30 ft cone for weakened state and 7th for 12d6 60 ft cone for awakened state) with the right save DCs and using only 1 charge. 

The user will need to add a custom action on the sheet for the extra damage to roll this more easily. 

I understand the limitation and challanges and hope for the best with the new gaming platform!

But I have one point... the workaround is to homebrew it, so how many of those homebrewed variant of thoses weapons exist and are filling the homebrew database?

Quote from Zero_D_Karma >>

I understand the limitation and challanges and hope for the best with the new gaming platform!

But I have one point... the workaround is to homebrew it, so how many of those homebrewed variant of thoses weapons exist and are filling the homebrew database?

 
Depends on how many groups are using Fizban's book, and how many of those have characters obtaining this item. Then how many of those bother homebrewing instead of just making custom actions or rolling the dice manually.

So, probably not many. ¯\_(ツ)_/¯