Here are my rules for the AF3 / FR1 / FP1
AF3= autofocuser
FR1 = Field Rotator
FP1 = Flat panel

SUBSYSTEM=="tty", ATTRS{idVendor}=="2341", ATTRS{product}=="Arduino Nano Every", ATTRS{idProduct}=="0058", ATTRS{serial}=="CDF0B4D451514746304B2020FF0A0328", SYMLINK+="FR1", KERNEL=="ttyACM*", MODE="0666"SUBSYSTEM=="tty", ATTRS{idVendor}=="2341", ATTRS{product}=="Arduino Nano Every", ATTRS{idProduct}=="0058", ATTRS{serial}=="902AE657515146544E4B2020FF0B3646", SYMLINK+="FP1", KERNEL=="ttyACM*", MODE="0666"SUBSYSTEM=="tty", ATTRS{idVendor}=="2341", ATTRS{product}=="Arduino Nano Every", ATTRS{idProduct}=="0058", ATTRS{serial}=="C4B1A01151514746304B2020FF0A1317", SYMLINK+="AF3", KERNEL=="ttyACM*", MODE="0666"

You will get in /dev :
root@heidenrod-obs:/dev# ll
total 4
drwxr-xr-x 16 root root        4860 Jul  1 17:38 ./
drwxr-xr-x 23 root root        4096 Mar 19 17:43 ../
lrwxrwxrwx  1 root root           7 Jul  1 17:38 AF3 -> ttyACM1
lrwxrwxrwx  1 root root           7 Jul  1 17:38 FP1 -> ttyACM0
lrwxrwxrwx  1 root root           7 Jul  1 17:38 FR1 -> ttyACM2