Internet connectivity

Subsequent to update to iPadOS14, your iPad is now better able to [warn] bring to your attention security deficiencies of your WiFi network and iPad settings. Your iPad now has more advanced capabilities in context of identifying and alerting you to potential network security issues.

This support page will describe the more secure (recommended) settings for WiFi:

Recommended settings for Wi-Fi routers and access points – Apple Support

Your iPad is no less secure today than it was prior to the update to iPadOS14. However, your iPad is now better able to [warn] bring to your attention security deficiencies of your WiFi network and iPad settings - as it now has more advanced capabilities in context of identifying and alerting you to potential network security issues.

Whist you are wise in paying attention to the warning - and you should indeed endeavour to improve the security of the WiFi connection - you very likely have no immediate cause for concern unless all security has been disabled.

As previously stated, this support page will describe the more secure (recommended) settings for WiFi:

Recommended settings for Wi-Fi routers and access points – Apple Support

Your ISP should, as a minimum, provide online resources that explain how to set-up and configure your WiFi Router. If your ISP cannot provide adequate help and support, perhaps you should consider changing to an alternative service provider.

Have tried looking at the Talk Talk support communities - and asking for help?