DIAGNOSIS: Your device is likely getting confused by a feature called Smart Connect, which automatically steers devices between the 2.4GHz and 5GHz bands. Sometimes it glitches and a device gets temporarily kicked off.
FIX: The most reliable fix is to split the bands so you control which network you're on. Log into the router's web interface (tplinkwifi.net). Go to Advanced > Wireless > Wireless Settings. Find the 'Smart Connect' option and turn it OFF. This will reveal separate settings for your 2.4GHz and 5GHz networks. Give each one a distinct name (like MyNetwork_2G and MyNetwork_5G) and save. Now, connect your phone directly to the 5GHz network. The random drops should stop.
IF THAT DIDN'T WORK: There could be interference from a neighboring network. In the same Wireless Settings menu, try changing the 5GHz 'Channel' from 'Auto' to a specific one, like 36, 40, 44, or 48. Avoid the DFS channels (like 52-144) if you're in a busy area, as they can cause the router to temporarily shut off the signal if it detects radar.
HEADS UP: Some older devices don't play nice with the newest WiFi 6 (802.11ax) mode. If you have an old laptop or smart plug acting up, you can try changing the 5GHz 'Mode' from '802.11ax/ac/n mixed' to just '802.11ac/n mixed'. You'll lose a bit of WiFi 6 efficiency, but it can improve stability for finicky gadgets.