bluetooth headset microphone profile unavailable

avinfo

$ sudo avinfo 88:D0:39:GG:GG:GG
Connecting ...
Stream End-Point #1: Audio Sink
        Media Codec: SBC
                Channel Modes: Mono DualChannel Stereo JointStereo
                Frequencies: 44.1Khz 48Khz
                Subbands: 4 8
                Blocks: 4 8 12 16
                Bitpool Range: 2-52
Stream End-Point #3: Audio Sink
        Media Codec: SBC
                Channel Modes: Mono DualChannel Stereo JointStereo
                Frequencies: 44.1Khz 48Khz
                Subbands: 4 8
                Blocks: 4 8 12 16
                Bitpool Range: 2-52
Stream End-Point #4: Audio Sink
        Media Codec: MPEG24
                Object Types: MPEG-2 AAC LC
                Frequencies: 44.1kHz 48kHz
                Channels: 1 2
                Bitrate: 264630
                VBR: Yes
Stream End-Point #2: Audio Sink *
        Media Codec: MPEG24
                Object Types: MPEG-2 AAC LC
                Frequencies: 44.1kHz 48kHz
                Channels: 1 2
                Bitrate: 264630
                VBR: Yes

pactl list cards

Card #1
        Name: bluez_card.88_D0_39_GG_GG_GG
        Driver: module-bluez5-device.c
        Owner Module: 33
        Properties:
                device.description = "Soundcore Life Q20"
                device.string = "88:D0:39:GG:GG:GG"
                device.api = "bluez"
                device.class = "sound"
                device.bus = "bluetooth"
                device.form_factor = "headset"
                bluez.path = "/org/bluez/hci0/dev_88_D0_39_GG_GG_GG"
                bluez.class = "0x240404"
                bluez.alias = "Soundcore Life Q20"
                device.icon_name = "audio-headset-bluetooth"
                device.intended_roles = "phone"
        Profiles:
                a2dp_sink: High Fidelity Playback (A2DP-Ziel) (sinks: 1, sources: 0, priority: 40, available: yes)
                headset_head_unit: Headset Head Unit (HSP/HFP) (sinks: 1, sources: 1, priority: 30, available: no)
                off: Aus (sinks: 0, sources: 0, priority: 0, available: yes)
        Active Profile: a2dp_sink
        Ports:
                headset-output: Headset (priority: 0, latency offset: 0 usec, available)
                        Part of profile(s): a2dp_sink, headset_head_unit
                headset-input: Headset (priority: 0, latency offset: 0 usec, not available)
                        Part of profile(s): headset_head_unit