@Samiran-B 

Please check and ensure the Transmit Power on the A7 is set to be High, then you may try to modify the wireless channel and channel width settings on it to monitor again. As for the 5G channel, you may try 36/40/44/48, channel width 80MHz; As for the 2.4G, you can change the channel to 1/6/11, channel width to 40MHz, or you may run a Wi-Fi analyzer to review the channel, then choose one with better signal.

Please also ensure the firmware on the A7 is up-to-date, you can try to reset it to factory defaults then reconfigure it from scratch to confirm.

2.4G and 5G network have their own advantages and disadvantages, generally. You may check this article to try to improve the coverage of the router:
https://www.tp-link.com/en/blog/87/6-tips-on-where-to-place-your-wireless-router-for-the-best-signal-coverage/