No sound detected by the internal microphone on a dell laptop

I'm running Ubuntu 18.04 on a Dell G3 15 3590. Had some problems already with the audio. To make it work I added snd_hda_intel.dmic_detect=0 to grub parameters, it made my internal audio work, but not my mic; then I added options snd-hda-intel model=headset-mic in alsa-base.conf. With this, my system recognizes internal mic, but no sound is detected.

The sound works without options snd-hda-intel model=headset-mic, but still mic don't detect any sound. On Discord voice testing, I hear echos of my internal audio, really weird. And when I plug only a headphone the system switches the input to headphone mic; and if I switch back the input to internal mic then audio stop working too (and still no sound on mic).

Had gone weeks already trying to find a solution, but nothing until now.