Hi there, doing one of my first campaigns and I want to make a completely new weapon, but home brew only has pre-existing magic weapons as choices for damage. I want to either A. Take the required "base weapon" damage off or B. Remove the "base weapon" entirely. Completely defeats the purpose if I can't make the damage its own.

That has since changed. When they originally gave DDB the green light to allow homebrew WotC said no basic equipment and sited a section from the DMG (excerpted below)  as to why new base equipment and new base classes shouldn’t be necessary in their opinion. They have since said both of those are okay, but there are so many other things that DDB has to prioritize that any overhaul to the homebrewer is waayyy down the road, my guess is 2023 at the earliest.

https://www.dndbeyond.com/sources/dmg/a-world-of-your-own#Wuxia

Wuxia

When a sensei disappears mysteriously, her young students must take her place and hunt down the oni terrorizing their village. Accomplished heroes, masters of their respective martial arts, return home to free their village from an evil hobgoblin warlord. The rakshasa master of a nearby monastery performs rituals to raise troubled ghosts from their rest.

[Sic]

Similarly, a class doesn’t need new rules to reflect a cultural influence; a new name can do the trick. A traditional Chinese wuxia hero might be a paladin who has a sword called the Oath of Vengeance, while a Japanese samurai might be a paladin with a particular Oath of Devotion (bushido) that includes fealty to a lord (daimyo) among its tenets. A ninja is a monk who pursues the Way of Shadow. Whether called a wu jen, a tsukai, or a swami, a wizard, sorcerer, or warlock character works just fine in a game inspired by medieval Asian cultures.

Wuxia Weapon Names

Having players refer to a tetsubo or a katana rather than a greatclub or a longsword can enhance the flavor of a wuxia campaign. The Wuxia Weapon Names table lists alternative names for common weapons from the Player’s Handbookand identifies their real-world cultural origins. An alternative name changes none of the weapon’s properties as they are described in the Player’s Handbook.

Quote from Fareyyy >>

Hi there, doing one of my first campaigns and I want to make a completely new weapon, but home brew only has pre-existing magic weapons as choices for damage. I want to either A. Take the required "base weapon" damage off or B. Remove the "base weapon" entirely. Completely defeats the purpose if I can't make the damage its own.

 You may be able to hack/fake what you want. Lemme know what you are trying to create and I’ll be able to tell you if that’s possible.

Nothing stopping you from creating a magic item that doesn't have any kind of power.

Hello everyone  how's thing going 

Was looking for a solution too, glad to know this aged well.
A feature planned for the future yeah? Thanks WOTC