I ordered lamp holders from AliExpress with an outer thread for a project, but they came without caps, so I made my own.
They work great for my use case and may be helpful to others as well.
Print recommendation: PETG over PLA, the small hooks tend to break off with PLA when slipping them on.
The lamp holders can be found here: https://de.aliexpress.com/item/1005006225510467.html
The author marked this model as their own original creation.