Same issue for me. Dramatical battery drain after upgrade to latest 14.4.2. iPhone Xs MT532CN/A. Please help!

Definitely there is issue with new IOS. I have Cisco 1815W AP with single SSID working on 2,5 and 5GHZ band. After I have upgraded to IOS 14.0.1 I had to separate SSID's for 2,5 and 5GHZ bands in order to be able to use iPhone Xs Max on WiFi. Upon band separation iPhone is not able to find 5GHz SSID for a long time. It gets many attempts before it can associate it self to the AP. Even when you manage to associate as soon as you start loading network traffic there is TTL exceeded message. Test I have done was standing directly below AP. Packet loss is present on both bands. Same time, Mac Book Pro Catalina reaches much higher download speeds without any packet loss on any of the bands. Same time, family members on older iPhone IOS and older phone models are heaving no issues.