pulseaudio – Asus Realtek ALC270 X450CA – Headset Microphone does not work [Ubuntu Focal Fossa]


I have the same issue reported in Microphone is not working | Zenbook model ux32la codec Conexant CX20751/2 | ALSA | ubuntu 20.04 and I did exactly all the same workarounds reported here https://bugs.launchpad.net/linuxmint/+bug/1359803 and here https://ubuntu-bugs.narkive.com/4Sm2w53J/bug-1359803-re-external-mic-not-being-used-in-combo-port without success. I’m still investigating. Does anyone knows how to fix this bug?

/proc/asound/card*/codec*

Codec: Realtek ALC270

System:    Kernel: 5.4.0-48-generic x86_64 bits: 64 Desktop: Xfce 4.14.2                                       
           Distro: Ubuntu 20.04.1 LTS (Focal Fossa)                                                                               
Machine:   Type: Laptop System: ASUSTeK product: X450CA v: 1.0 
           Mobo: ASUSTeK model: X450CA v: 1.0  UEFI: American Megatrends v: X450CA.206           
           date: 08/01/2013                                                                                                       
Audio:     Device-1: Intel 7 Series/C216 Family High Definition Audio driver: snd_hda_intel                                       
           Sound Server: ALSA v: k5.4.0-48-generic