@Sauravm22 

Yes, all the lower-end range extenders from TP-Link provide only 100 Mbps Ethernet ports. That means you are limited to a maximum speed of 100 Mbps when connected to the RE205 via Ethernet cable.

https://www.tp-link.com/en/home-networking/range-extender/re205/#specifications

For faster Ethernet speeds (1000 Mbps) you would have to get a model RE450 or better.

  @woozle Will RE305 work? I just need to reach 200mbps with the lan port. Also I checked that it's recommended to have 1200mbps extender if the user has 200mbps internet speed. So will the RE305 work?

  @Sauravm22 

No, the RE305 also has an 100 Mbps Ethernet port.

https://www.tp-link.com/en/home-networking/range-extender/re305/#specifications

You can easily check which range extenders are suitable for your needs via TP-Link's product webpage for range extenders.

https://www.tp-link.com/home-networking/range-extender/

  @woozle so if i buy re405, do i need to purchase a newer lan cable? I dont know if its necessary to buy a new cable to reach 200mbps. Currently I have a grey colored lan cable.

  @Sauravm22 

The color of the cable doesn't tell what speeds are possible.

Look for markings on the Ethernet cable like "Cat 5e" or "Category 5E" or "Gigabit". If you see these markings or markings with even higher numbers (like Cat 6, Cat 6a, Cat 7), then this cable is sufficient for use with a RE450.

  @woozle ok, so i checked the cable and Cat 5E is written along with 100 ohm. What does this ohm do?

  @Sauravm22 

The typical impedance of Ethernet cable is standardized as 100 Ohm.

Usually the manufacturers omit the "100 Ohm" marking on their cables. But still, Ethernet cables without a "100 Ohm" marking still have (or should have) an impedance of 100 Ohm.

  @woozle OK, so if i get the RE450 and Cat6/Cat7 cable, I would be able to reach 200mbps right?

  @Sauravm22 

As I mentioned earlier, any cable rated Cat 5e or better is sufficient for the RE450. (provided your Cat 5e cable is of good quality)

The RE450 has a Gigabit Ethernet port. https://www.tp-link.com/en/home-networking/range-extender/re450/#specifications
This will remove the 100 Mbps bottleneck of the RE205's Ethernet port.

Then the Wi-Fi connection will become the new bottleneck.
How fast your Wi-Fi connection is going to be is hardly predictable. It depends on the capabilities of the Wi-Fi router and the distance between the router and the RE450.

Don't expect to reach 200 Mbps on the 2.4 GHz band with the RE450.