pi@raspberrypi:~ $ cat /etc/udev/rules.d/90-lte.rules
ACTION=="add", SUBSYSTEM=="net", ATTR{address}=="0c:5b:8f:27:9a:64", RUN+="/usr/local/bin/lte_setup.sh"
pi@raspberrypi:~ $ cat /usr/local/bin/lte_setup.sh
#!/bin/sh

sleep 2
mmcli -m 0 --simple-connect='apn=internet.t-d1.de,user=t-mobile,password=tm,number=*99#'