@Nishankg a bigger gap may do better if possible ...and the vertical mount is a good idea as hot air goes up, unlike in horizontal position where it accumulates beneath

@Nishankg also position your router so there is some air flow underneath ... i suspect this problem is a result of excessive overheating ... put it on PET bottle caps for example

@Nishankg try switching transmit power to medium or low ... had same problems and this helped me ... but also please contact TP-Link support as this looks like a design flaw and they need to be...