The extra software you need for bluetooth is already installed on ArcoLinux but not on ArcoLinuxD.
sudo pacman -S pulseaudio-alsa pulseaudio-bluetooth
sudo pacman -S bluez bluez-libs bluez-utils bluez-firmware blueberry
sudo systemctl enable bluetooth.service
sudo systemctl start bluetooth.service
sudo systemctl daemon-reload
Sometimes you need to switch your headset off and on again to reconnect to your machine when you reboot your computer.
Enable pairing on your headphone.
Go to the bluetooth icon, click on the bluetooth icon and connect to your device.
Go to the sound icon (bottom right) and select your device.
See that the Output profile is High Fidelity Playback (A2DP sink). MUCH better sound than the other setting Headset Head Unit (HSP/HFP). As long as you do not see this headphone in your sound settings, you guess it, something is wrong. And in bluetooth nothing seems that simple. Then you can start googling. May I suggest the archlinux guide as a start. I hope the installation was a success. A screenshot of the settings in pavucontrol.
Use the buttons on your headphone for volume handling
Use the middle (multi-function) button for the next song (double click)
Use the middle (multi-function) button for the previous song (three clicks)