Very slow speeds intermittently on Android TV (mi tv) connected to 2.4ghz band of Archer c6

Devices connected to 5ghz band work flawlessly buy my tv doesn't have 2.4ghz connectivity

Tried changing channel width and switching to channels 1,6,1. Upgraded to latest firmware. Issue persists. Sometimes it works when I disconnect or reboot and after sometime, again streams start buffering

Haven't faced an issue with the tv when its connected to my old router, so I'm pretty sure it's router specific

Please suggest a fix.