gistfile1.txt

this will force the connection to your bluetooth headphones:

sudo nano /bin/connect-bluetooth.sh

In that file add
#!/bin/bash
sudo bluetoothctl << EOF
power on
connect [MAC Address]
exit
EOF

Save that file.
Make it executable

sudo chmod +x /bin/connect-bluetooth.sh

Then create a new file
sudo nano /etc/systemd/system/connect-bluetooth.service

Add this text:
[Unit]
Description=Connect Bluetooth

[Service]
Type=oneshot
ExecStart=/bin/connect-bluetooth.sh

[Install]
WantedBy=multi-user.target
Save that file.

Then run this command to enable that process
sudo systemctl enable /etc/systemd/system/connect-bluetooth.service