NitroPad X230 WiFi signal issues

I noticed that the WiFi signal of my NitroPad X230 is not that well. When other devices such Smartphones and other Notebooks got 100 % signal strength the Nitropad has around 85 %.

Is that a common Lenovo X230 problem with an Intel 802.11b/g/n 2200N Wifi module?
Does the Notebook support WPA3? In Ubuntu 20.04.1 LTS I can select WPA3, but it wont establish a connection, so I have to switch to WPA2.