@ukanonymousuk I reinstalled my old MediaTek card, and all the problems have been resolved. Thanks to all for advices.

@woozle I haven't checked it with the old card; I got the router and the card on the same day and set everything up at once. I'll check for ARP, thanks.

@ukanonymousuk I've tried a wired LAN connection for the laptop, but the result is the same—all other devices lose internet access as soon as the laptop is active.

Dear All, After purchasing this router, it updated immediately. I also upgraded the network card in my laptop to an Intel AX210. Now, whenever I connect the laptop to the Wi-Fi, the connection drops...