(clueless) Bought a router, thought it could give internet from inserting micro-sim card. Help

I don't have cable internet to the house I currently live in, I rely on the wifi - internet from my mobile. (micro-sim). I thought I could buy that product and insert the sim-card and it would give me better wifi connection.

Then I realised it has no place to insert the card so I started googling and now I know the difference between Router and Modem. Great.

Here is where I know nothing. If I buy a modem, will it work with a microsim or do I need cable internet to connect to it and the router only makes the cable internet into wifi. Or do I have to buy a router modem hybrid?

basically I'm just asking, is my router a completely wasted purchase if I don't have cable internet, or can I somehow utilize it with micro-sim wifi depending on which modem I buy?

Please help, I'm clueless about these things