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. Your iPad now has [arguably] more advanced capabilities than your Mac 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
It is possible that your WiFi Router is too old to be (or not capable of being) configured for more secure settings. As such, you can either configure the most secure settings that your Router will support - or replace your Router with something more advanced that provides better security configuration options.
TKIP is old and insecure - and was deprecated many years ago; it should be disabled in deference to much better WiFi security protocols (WPA2 and WPA3).
You’ll need to consult your specific WiFi Router configuration documentation to determine how to update your router settings or firmware. If the router was supplied by your Internet Service Provider, they may have a support webpage that provides appropriate guidance on accessing and updating settings.