ChatGPT isn't wrong - this sounds like what you need: https://pypi.org/project/zero-hid/.
(I would use it to use a laptop keyboard on a headless computers).
I am looking for an easy solution, it does not have to be the cheapest.
ChatGPT points me to Arduino, but as far as I can see, there's no arduino with 2 usb ports. It also points me to Raspery pi zero, but that's a computer, not a microcontroller, so not sure if it's suitable.
If anyone with experience can give me some pointers, it would be greatly appreciated!
ChatGPT isn't wrong - this sounds like what you need: https://pypi.org/project/zero-hid/.
I am unfamiliar with Raspberry pi, but if my understanding is correct, it's running a real os. So I would need to send it a command to actually shut down every time I want to remove the usb device. More generally, having a general purpose OS on the little device seems overkill for that use case, no?
You could use an rpi pico. It has a usb port and there is a software hack to bit bang a second usb port, iirc.