Before buying a router, you should study its detailed specifications mentioned on the manufacturer product page. For Archer C60 it’s here Archer C60 | AC1350 Wireless Dual Band Router | TP-Link India
You have 300Mbps connection, but as per specs C60 only has 100Mbps WAN & LAN ports, which means the data from ISP can come into the router at thruput of Max 100Mbps. (Assuming you are connected to ISP by Ethernet cable at WAN port) Now the 5Ghz band of C60 theoretically operating at 867Mbps is of no use as it will still be capped at 100Mbps due to the 100Mbps limitation of WAN port. Hope it’s clear.
Also note that the ISP speed is what you can possibly aim to get on Wired Ethernet connection, actual WiFi speeds can be lower than that due to several constraints and limitations.
Go for a Dual Band router that has 1Gbps (1000Mbps) WAN & LAN Ports, only then you can enjoy actual 300Mbps connection at least on Ethernet. Specs should read Gigabit or Gbps or 10/100/1000Mbps like that.