How do I change the default damage die for a homebrew weapon?

As the title said, I wanted to homebrew a "Common" weapon and I wanted the damage die to be different. I was able to locate the (Weapon Property) In the modifier menu, but there isn't an option for replacing the weapon's default damage die (although I could add in extra damage). Is there anyways to change it?

Also, is there any way to add custom Versatile damage?

You cannot change a weapon base damage die, as for the versatile property, adding it will automatically add the option for a dice category higher, but it isn't customizable.