I am currently working on a Minecraft 1.19 mod, and I am trying to create a feature where the item in the player's hand becomes invisible when a certain condition is met. For example, I have an item that makes the player invisible, and I would like to make the item in the player's hand also become invisible along with the player. I am having trouble figuring out how to implement this feature and would greatly appreciate any help on how to do this.

can you make it change sprite depending on condition (like clock or a bow)? once you have that, having one piece of png file transparent should do the job.

disclaimer: haven't tried.

I'm trying to do this for every item that the player is holding.

i was thinking in that back in 1.12 when i was doing the guns 
but mi plans was to make a holder item something like an small box but in the json display firstperson/left/right hand set the size to 0.0  this box has an nbt container whit only one space for an itemstack and to avoid missing the item the box count 20 ticks in OnUpdate() and delete itself returning the stored itemstack back to that hand slot 

well is not easy solution i never do the code for that 
may is posible to delete the rendered arm for the client side or something the bow does