Astro A50 support on Linux - basic configuration for PulseAudio 13 (tested on Ubuntu's 13.99.1). Install the files and reboot, to make sure udev and PA reloaded :-)

PA profile-set astro-a50-gen4.conf

; /usr/share/pulseaudio/alsa-mixer/profile-sets/astro-a50-gen4.conf

[General]
auto-profiles = yes

[Mapping analog-voice]
description = Voice
device-strings = hw:%f,0,0
channel-map = left,right
paths-output = steelseries-arctis-output-chat-common
intended-roles = phone

[Mapping analog-voice-input]
description = Voice
device-strings = hw:%f,0,0
channel-map = mono
paths-input = usb-gaming-headset-input
intended-roles = phone

[Mapping analog-game]
description = Game
device-strings = hw:%f,1,0
channel-map = left,right
paths-output = steelseries-arctis-output-game-common
direction = output

[Profile output:analog-voice+output:analog-game+input:analog-voice]
output-mappings = analog-voice analog-game
input-mappings = analog-voice-input
priority = 5100
skip-probe = yes

udev 90-astro-50.rules

# /etc/udev/rules.d/90-astro-50.rules

# ID 9886:002c is for Astro A50 Gen4
ACTION=="change", SUBSYSTEMS=="usb", ATTRS{idVendor}=="9886", ATTRS{idProduct}=="002c", ENV{PULSE_PROFILE_SET}="astro-a50-gen4.conf"

I've built pulseaudio with your guide and started it with your command (after removing the .libs from your -p argument as PA was appending this already).
Also I changed the udev rule to be ACTION=="change", SUBSYSTEMS=="usb", ATTRS{idVendor}=="9886", ATTRS{idProduct}=="0015", ENV{PULSE_PROFILE_SET}="/home/$USER/Downloads/pulseaudio/paudio/src/modules/alsa/mixer/profile-sets/usb-gaming-headset.conf" (but with my user name instead of $USER)
But still I'm only getting one output device which is called Headphones - A50.

This time changing the channel-map was not the solution to it, so I created a new path/copied the stereo path called usb-gaming-headset-output-game (src/modules/alsa/mixer/paths/usb-gaming-headset-output-game.conf) and used it in the stereo-game section.
And with this it worked! However it still needs to have the extended channel-map.

I also got you some logs starting from the point when I plugged in the headset

• Without my changes: https://hastebin.net/pobepomoge.yaml
• With my changes: https://hastebin.com/tukekiligu.yaml

Hope it helps

I have the strange problem that my Microphone just stop working after some time and I have to switch the profile in pavucontrol. Sometimes its work for 1-2 Days ... and then its starting to work only for 15 Seconds and I have all 15 Seconds to switch the profile, else nobody can hear me .... very very strange! -.-

have anyone got Gen 3 version working?

have anyone got Gen 3 version working?

just changde idProduct in udev rules. gen 3 has probably 0015 instead of 002c.
you might check it with lsusb | grep 9886

Is this expected to work with pipewire?

Is this expected to work with pipewire?

it won't, but not required.

just execute one of the following commands:
sh -c 'pactl set-card-profile alsa_card.usb-Astro_Gaming_Astro_A50-00 pro-audio; pactl set-default-sink alsa_output.usb-Astro_Gaming_Astro_A50-00.pro-output-0; notify-send -i audio-headphones "Sound Output:" "Astro 50 Voice"'
or
sh -c 'pactl set-card-profile alsa_card.usb-Astro_Gaming_Astro_A50-00 pro-audio; pactl set-default-sink alsa_output.usb-Astro_Gaming_Astro_A50-00.pro-output-1; notify-send -i audio-headphones "Sound Output:" "Astro 50 Game"'

in the latest case your headset will get the equalizer and dolby surround