In fact, changing the DNS settings on your LG Smart TV is fairly straightforward if you enable Developer Mode. Custom DNS servers can potentially improve your streaming quality and connectivity. 

However, be very careful when entering DNS server addresses, as incorrect settings can prevent your LG TV from connecting to the Internet.

If you experience any issues with connectivity after changing the DNS settings, you may need to perform a factory reset of your LG Smart TV to restore the default settings.

Here are 10 troubleshooting tips for when you change the DNS settings on your LG Smart TV:

1. Make sure you enter valid DNS server IP addresses. Incorrect IP addresses will prevent the TV from connecting to the Internet.

2. Double check that the DNS server addresses are for your network type. Use IPv4 addresses for most home networks. If using IPv6, make sure your router and ISP support it.

3. Ensure Developer Mode is enabled when entering custom DNS settings. You must turn on Developer Mode to access the advanced network menu where you can change DNS servers.

4. Re-enter your network password after changing DNS settings. Even though you're using the same Wi-Fi network, changing DNS settings may require re-entering your password to re-connect.

5. Restart your LG TV after entering new DNS servers. A simple restart is required for the new DNS settings to take effect.

6. Check for software updates on your LG TV. New updates may overwrite your custom DNS settings and reset them to default. Check for updates before changing DNS servers.

7. Make sure your router allows external DNS server access. Some routers block usage of third-party DNS services for security. You may need to enable DNS access on your router.

8. Try restarting your router after restarting the TV. In rare cases, restarting just the TV may not be enough for the new DNS settings to propagate on your network. A router restart helps ensure everything is refreshed.

9. Make sure the new DNS service you're using is compatible with LG TV streaming services. Some services may block certain streaming platforms, which can impact your LG TV functionality.

10. Perform a factory reset if problems persist. As a last resort, you may need to factory reset your LG Smart TV to restore default network settings and start troubleshooting from the beginning. Only reset if other options have not resolved your issues.

Hope this guide helps you improve your LG Smart TV's performance! Let me know if you have any other questions.