My ISP upgrading their network and so they'll have 10gbps connection early next year. Right now it's 1gbps down / 300mbps up. My setup as for now contains the ISP's modem that receives the optical cable and forwards to my Asus AC68U router on ethernet. I also have a 1TB HDD hooked up to the router.
Our appartement is relatively small (45 sqm) so wifi signal is not a problem usually.
I'd like to ask you what router would you recommend to be able to use that 10gbps with atleast 1 USB port?
Your not gong to find an off the shelf consumer solution. Hell consumer grade routers still have problems with Gigabit Internet. You might look in to building a PFsense box. But without knowing how the ISP is going to connect you up its hard to say. For example my ISP Comcast offers 3 Gbps symmetrical Fiber at an exorbitant cost. The media converter they use at the home has 1x 1Gbps Ethernet and 1x 10Gbps SFP ports. But 10 Gbps over Ethernet is also a thing, so you will need to wait and see what they do. Ether way, PFsense might be your only option or buying some enterprise grade solution.