Do you think I could get better performances with a more powerfull router

How can we tell when you didn't tell us what you have now?
But bonehead is right. Your true "internet" speeds are going to depend on your service agreement with your ISP and on the capability of your current "modem" and not your router - unless your router is really REALLY old and using very obsolete wifi protocols and 10/100 Mbps Ethernet.
It is important to understand the differences between the various network devices. Technically the cable/DSL modem, router, WAP (wireless access point or AP) and 4-port Ethernet switch are all
totally separate, "
discrete" network devices.
1. A modem (modulator/demodulator) is used as the "gateway device" to provide your network access to the ISP's network and the Internet.
2. A router has just one “wired” input and one “wired” output and is used to connect (or isolate) two networks. In a home network a router connects "your network" (the router and everything on your side of the router) to the ISP's network (and the Internet) through the gateway device/modem.
3. A Ethernet switch (also called a switching hub) is used to connect via an Ethernet cable, multiple networked devices on your network to the one input port on your side of the router.
4. A WAP is used to provide wireless (Wifi) access to your network. The WAP actually connects internally to a 5th Ethernet port of the switch.
Technically speaking, there is no such thing as a "wireless router". That is simply a "marketing" term for a "3-way" "integrated" device consisting of a router, a Ethernet switch (typically 4-port), and a WAP. These are three
discrete network devices that just happen to share the same box, same PCB (printed circuit board) and same power supply. Note the 4-port switch connects internally to the router's one input. And the WAP actually connects internally to a 5th Ethernet port of the switch.
In recent years manufacturers have also been integrating a modem with "wireless routers" for a 4-way integrated device. Four
discrete devices in one box. These are "marketed" under different terms like "residential gateway" devices, "wireless modems" or " wireless modem/routers".
In some cases, they even have 5-way devices that integrate Internet phone (voice over IP or VoIP) too. Five discrete devices, in one box.
So you need to tell us what you currently for your network devices. The most common provided by ISPs are a single, "residential gateway" integrated device - that is, the router, modem, WAP and 4-port switch in one box.
Also common is an ISP provided modem, connected (via Ethernet) to a separate "wireless router" (router, WAP, switch).
But note this. That Gigabyte adapter supports 802.11ax - up to 2400Mbps. It is NOT your problem.