The USB stick is to become a mobile hotspot. In other words, it is to enable Internet access via SIM in the USB stick via tplink. That's what it's there for, but it doesn't have a SIM slot itself (see the picture of the USB connection where it says 3G/4G).
I already had the Huawei stick and therefore wanted to do it with this product instead of running a standalone mobile hotspot for over 100 euros that has a SIM slot.
And with this one, it should actually work. The stick should be supported.

Hello. I don't understand...this is already a router...why do you want to connect a USB stick that is also a router?