systemd unit for wpa_supplicant & dhclient on trisquel (Ubuntu)

Hello! I cannot see networkmanager's slow work. I disabled NetworkManager and wpa__supplicant services this way:

# systemctl disable NetworkManager
# systemctl disable NetworkManager-wait-online
# systemctl disable wpa_supplicant

also I deleted dnsmasq for prevent possible errors.

I connect via wpa_supplicant & dhclient usig this config and this line:

# cat /etc/wpa_supplicant/wpa_supplicant.conf
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=sudo
update_config=1

network={
ssid="internet"
scan_ssid=1
psk=hashlonghash
proto=RSN
key_mgmt=WPA-PSK
}

# /sbin/wpa_supplicant -B -i wlp1s0 -c /etc/wpa_supplicant/wpa_supplicant.conf && /sbin/dhclient wlp1s0

Now I want to add this line to systemd. I created Unit that does not work:

# cat /etc/wpa_supplicant/wpa_supplicant_my.service
[Unit]
Description=Start WPA Supplicant and Dhclient
After=network.target

[Service]
Type=oneshot
ExecStart=/sbin/wpa_supplicant -B -i wlp1s0 -c /etc/wpa_supplicant/wpa_supplicant.conf && /sbin/dhclient wlp1s0
ExecStop=/usr/bin/killall -q wpa_supplicant && /usr/bin/killall -q dhclient
#RemainAfterExit=true
#TimeoutStartSec=5sec

[Install]
WantedBy=multi-user.target

# systemctl link /etc/wpa_supplicant/wpa_supplicant_my.service

# systemctl start wpa_supplicant_my.service
Job for wpa_supplicant_my.service failed because the control process exited with error code. See "systemctl status wpa_supplicant_my.service" and "journalctl -xe" for details.

# systemctl status wpa_supplicant
● wpa_supplicant_my.service - Start WPA Supplicant and Dhclient
Loaded: loaded (/etc/wpa_supplicant/wpa_supplicant_my.service; linked; vendor preset: enabled)
Active: failed (Result: exit-code) since Сб 2018-06-16 22:41:26 +03; 14s ago
Process: 1412 ExecStop=/usr/bin/killall -q wpa_supplicant && /usr/bin/killall -q dhclient (code=exited, status=1/FAILURE)
Process: 1409 ExecStart=/sbin/wpa_supplicant -B -i wlp1s0 -c /etc/wpa_supplicant/wpa_supplicant.conf && /sbin/dhclient wlp1s0 (code=exited, status=
Main PID: 1409 (code=exited, status=0/SUCCESS)

июн 16 22:41:26 asus systemd[1]: Starting Start WPA Supplicant and Dhclient...
июн 16 22:41:26 asus wpa_supplicant[1409]: Successfully initialized wpa_supplicant
июн 16 22:41:26 asus systemd[1]: wpa_supplicant_my.service: Control process exited, code=exited status=1
июн 16 22:41:26 asus systemd[1]: Failed to start Start WPA Supplicant and Dhclient.
июн 16 22:41:26 asus systemd[1]: wpa_supplicant_my.service: Unit entered failed state.
июн 16 22:41:26 asus systemd[1]: wpa_supplicant_my.service: Failed with result 'exit-code'.

# systemctl enable wpa_supplicant_my.service
Failed to execute operation: Too many levels of symbolic links

# /sbin/wpa_supplicant -B -i wlp1s0 -c /etc/wpa_supplicant/wpa_supplicant.conf && /sbin/dhclient wlp1s0
Successfully initialized wpa_supplicant

# ps -aux | grep -e wpa -e dhclient
root 1405 0.0 0.0 26108 3456 pts/0 T 22:41 0:00 systemctl status wpa_supplicant_my
root 1461 0.0 0.0 52476 3140 ? Ss 22:44 0:00 /sbin/wpa_supplicant -B -i wlp1s0 -c /etc/wpa_supplicant/wpa_supplicant.conf
root 1563 0.0 0.0 16124 860 ? Ss 22:44 0:00 /sbin/dhclient wlp1s0
root 1565 0.0 0.0 14188 928 pts/0 S+ 22:44 0:00 grep --color=auto -e wpa -e dhclient

# systemctl stop wpa_supplicant_my

# ps -aux | grep -e wpa -e dhclient
root 1405 0.0 0.0 26108 3456 pts/0 T 22:41 0:00 systemctl status wpa_supplicant_my
root 1461 0.0 0.0 52476 3140 ? Ss 22:44 0:00 /sbin/wpa_supplicant -B -i wlp1s0 -c /etc/wpa_supplicant/wpa_supplicant.conf
root 1563 0.0 0.0 16124 860 ? Ss 22:44 0:00 /sbin/dhclient wlp1s0
root 1569 0.0 0.0 14188 1092 pts/0 S+ 22:44 0:00 grep --color=auto -e wpa -e dhclient

Please, why it does not enable with error: Failed to execute operation: Too many levels of symbolic links ???
Why it does not kill processes when stops and why id does not start?