As announced 126 days ago, AJG: Advanced Items is here at last! Featuring a new, much more intuitively understandable user interface, as well as introducing AJG Documentation and allowing us to generate all kinds of 1.16.100 [EX] custom items: swords, armor, projectiles, block and entity placers...

The delay after the initial announcement is due to the instability of MCBE's custom items capabilities documentation back then, and partly to some personal issues and lack of time for development. Nevertheless, AJG: Advanced Items is now finished and published, and will be maintained and updated when needed.
Since it's a sister project of the classic AJG, which will be updated accordingly soon, it is usable with it and shares the same support discord.

Enjoy!