@goryo 

Its been a while since I looked at a CPE, but I would recommend you try the following

Enable MaxStream

Change the bandwidth to 40mhz (anything but 10mhz)

@Philbert 

 I've changed the channel width to 20/40 mhz, and noticed the difference. My client is now reaching around maximum of 30mbps but its not stable. Is there other factors that affect the stability of the connection?

@goryo 

Hey again

Glad that increased the speed for you!

In relation to stability, you could try the following.

1.  Enable MaxStream - seen this help to stabilize speeds in previous setups.   Enable and test for a bit, its a TP Link standard but had good success with it.

2.  Try changing the channel, as you are running on 2.4ghz you will be using a very congested frequency range.  Most people will be broadcasting on  1   6  or 11    personally I would try each one individually see what is best..   OR  go to channel 13 if you are allowed in your country, its generally un-used.

Give those at try