Hello  @HyperMR ,

Welcome to our community.

Here are some troubleshooting steps to help resolve this:

For the internet connection drops:

1. Connect a PC directly to your modem (bypassing the router) to verify whether the instability is coming from your ISP or the router itself.
2. Check that the Ethernet cable between your modem and the router is firmly connected — try replacing it with a new CAT5E or higher cable if possible.
3. Change the DNS servers on your router: log into the web interface (http://tplinkwifi.net), go to Advanced > Network > Internet > Advanced Settings, and set the two DNS servers to 1.1.1.1 and 8.8.8.8.

For the wireless Tx rate drops affecting client devices:

1. Make sure the router is placed in an open area, not inside a cabinet or on a shelf.
2. Since you're already on channel 11 (2.4GHz) and channel 48 (5GHz), try switching to a few different channels on each band to see if nearby interference is contributing to the issue.
3. Check that none of your devices are included in any Parental Control profiles (log into the web interface > Advanced > Parental Controls, or check via the Tether app).
4. Make sure the network adapter drivers, operating systems, and firmware on your client devices (phones, laptops, smart devices) are all up to date.