Item Effects

Here's a description you can use:

Item Effects adds a simple command that lets you bind potion effects to any item. When you hold or wear the item, you automatically receive the effect — put it away and it fades after a few seconds.
Features

Bind any potion effect to any item — sword, armor, tools, anything
Works in main hand, off hand, and all 4 armor slots
Stack multiple effects on the same item
Effects are stored on the item itself, so they survive restarts and work when traded to other players
Effect icon shows in the HUD, no particle clutter

Commands
All commands require operator level 2.

/itemeffect add minecraft:strength — add Strength I to the held item
/itemeffect add minecraft:strength 1 — add Strength II (0 = level 1, 1 = level 2, up to 10)
/itemeffect remove minecraft:strength — remove a specific effect
/itemeffect list — list all effects on the held item
/itemeffect clear — remove all effects from the held item

Tab completion is supported for all effect names.
Use Cases

Enchanted armor that grants speed or regeneration while worn
A legendary sword that gives strength when held
A cursed item that applies weakness

Requirements

Minecraft 26.1.2
Fabric Loader 0.18.4+
Fabric API