Yes, that was good syntax, “-aG group user” not “-aG user group”
$groups now shows i am part of root (unsure if it is good idea security-wise, i would think better to grant permission just for single utility or a bash script)
apparently logout/login at non-gui tty (Ctrl+Alt+F5 and then Alt+F7) not sufficing to make the binary executable without sudo or not demand password when sudo is used. I will update this once i login/logout gui session / reboot. Thank you for the effort in the meantime @Mirdarthos .
btw.
$ sudo grep me /etc/sudoers
me ALL=(ALL) NOPASSWD:/usr/bin/wondershaper
me ALL=(ALL) NOPASSWD:/home/me/scripts/bwlimitmonitor