Default wireless bluetooth sound is HSP/HFP when i connect

Whenever i connect my wireless bluetooth headset, i am always set to default on HSP/HFP. I will always have to manually set to a2dp in my sound setting after connecting the bluetooth headset. How do i set the default to be a2dp instead of HSP? Note that my sound is working perfectly in both a2dp and hsp but i just want to stop manually switching whenever i connect

When i run pacmd list-cards

I get

...
...
    index: 19
    name: <bluez_card.00_00_B0_0A_49_39>
    driver: <module-bluez5-device.c>
    owner module: 47
    properties:
        device.description = "RHA TrueConnect"
        device.string = "00:00:B0:0A:49:39"
        device.api = "bluez"
        device.class = "sound"
        device.bus = "bluetooth"
        device.form_factor = "headset"
        bluez.path = "/org/bluez/hci0/dev_00_00_B0_0A_49_39"
        bluez.class = "0x240404"
        bluez.alias = "RHA TrueConnect"
        device.icon_name = "audio-headset-bluetooth"
        device.intended_roles = "phone"
    profiles:
        headset_head_unit: Headset Head Unit (HSP/HFP) (priority 30, available: unknown)
        a2dp_sink: High Fidelity Playback (A2DP Sink) (priority 40, available: unknown)
        off: Off (priority 0, available: yes)
    active profile: <a2dp_sink>
    sinks:
        bluez_sink.00_00_B0_0A_49_39.a2dp_sink/#40: RHA TrueConnect
    sources:
        bluez_sink.00_00_B0_0A_49_39.a2dp_sink.monitor/#62: Monitor of RHA TrueConnect
    ports:
        headset-output: Headset (priority 0, latency offset 0 usec, available: unknown)
            properties:
                
        headset-input: Headset (priority 0, latency offset 0 usec, available: unknown)
            properties:
                

I suspect it has something to do with the priority of a2dp_sink being higher than the headset_head_unit. If that is the problem, how do i modify the priority? Or if that is not the problem, how do i solve this annoying problem? I am on ubuntu 18.04