Summary

I couldn't find a portable small lamp that could be charged with a USB cable, so I built one.
The socket is made to fit an e26 or e27 led light bulb. The socket is not fixed to the cover, so you can replace it if you want to connect a different light source.
A 18650 type Li-ion battery was used.
I used a micro usb charging module, but a ubs c chraging module should fit as well. If not you can text me ad I will change it.
I used heated inserts to fit the threads into the holes for the screws.
I used double sided tape to fix the parts in place.
The part files are also included in case you want to modify something.

Here are the parts i have used:

Rocker switch:
https://de.aliexpress.com/item/1005005355220346.html?spm=a2g0o.order_list.order_list_main.23.66a15c5flvJuEQ&gatewayAdapt=glo2deu

Step up converter:
https://de.aliexpress.com/item/1005006011018786.html?spm=a2g0o.order_list.order_list_main.29.66a15c5flvJuEQ&gatewayAdapt=glo2deu

Light bulb 5W E27 DC12V, Warm White:
https://de.aliexpress.com/item/32965250856.html?spm=a2g0o.order_list.order_list_main.35.66a15c5flvJuEQ&gatewayAdapt=glo2deu

For the TP4056 battery charger micro usb modul I used a swiss suplier found here:
https://www.elektronik-kaufen.ch/products/tp4056
A similar product that should also fit can be found here, although I haven't tested it:
https://de.aliexpress.com/item/1005005708749053.html?spm=a2g0o.productlist.main.3.de74EKPZEKPZtW&algo_pvid=e5e47de3-f6ef-46c2-8907-0c65be48f250&algo_exp_id=e5e47de3-f6ef-46c2-8907-0c65be48f250-1&pdp_npi=4%40dis%21CHF%216.73%213.23%21%21%217.61%21%21%402101fb1117028126915727219eec07%2112000034078976187%21sea%21CH%213354495888%21&curPageLogUid=SQ8McTsKmmvg

Heated inserts:
https://de.aliexpress.com/item/1005004782336274.html?spm=a2g0o.order_list.order_list_main.41.66a15c5flvJuEQ&gatewayAdapt=glo2deu