HELP! Xbox party can't hear me, I can hear friends

Okay, so I have tried and read literally everything on the internet. I spent an hour on the phone with Microsoft support and they couldn't fix it. They told me as a last resort I could post here.

THE PROBLEM: I was playing a game with a friend in party chat when all of a sudden he couldn't hear me. We gave up playing thinking it would be a temporary issue. That was 3 weeks ago.

THE SOLUTIONS (that haven't worked):

1) The Xbox knows my mic is plugged in and it is not muted.

2) I have tried my headset on both of my controllers.

3) I tried connecting to a party on my phone through the Xbox App, but I got the same result where I can hear friends but they can't hear me. This happens both on WiFi and on LTE.

4) Tested it with many different friends, none of them have me muted.

5) Restarted my Xbox by holding down the power button for 10 seconds - as well as unplugging it from the back.

6) Logged out of my account and back in.

7) Checked every audio setting I could find on my account, everything looks normal.

8) Reset my console (kept games and apps installed). I have done this twice - once where I removed my account from the Xbox beforehand.

9) I have restarted my Modem and Router (I am wired to the Router)

10) I have checked my routers NAT settings (even though my Xbox says I have Open NAT).

11) My router doesn't have a UPnP setting, but I have gone through the process of turning off NAT-PMP, restarting router/xbox, turning on NAT-PMP, and restarting the router and modem.

12) Microsoft support confirmed that there are no communication bans or anything else on my account. Everything looks normal from their end.

As far as I can tell, this can't be a hardware issue since I can replicate the problem using the Xbox App on LTE. Something has to be wrong with my account. It can't be a problem with my settings, because the problem started in the middle of playing with
a friend (there is 0% chance that I accidentally changed an audio setting).

It is getting really annoying having to use a secondary device on Discord (and making my friends do the same) in order to play games and chat with them. As someone who has been given the responsibility of troubleshooting all of my extended family's technical
problems, I have seen a lot of weird stuff. This has me COMPLETELY stumped.... HELP!

Have you tried with a different Headset? maybe your mic is simply broken, so all the solutions tested haven't worked because the prerequisite is "headset working".

Didn’t have a second account on my xbox so i made one. It worked for a second and then cut out and wouldn’t come back. I had noticed similar behavior on my normal account after i reset my xbox, but i wasn’t sure if sound was actually going through because
i didn’t have someone on the other end at that time.

Hi!

Hope this helps

https://support.xbox.com/en-US/xbox-one/console/troubleshoot-xbox-one-party-audio

can you test with a different account on your Xbox to see if it is only with a problem with your account or whether it is your Xbox?

just starting a Party and testing to see if the blue ring shows will be enough.

edit to add:

although you have checked the audio settings, go to the mic sensitivity and move the slider to one end and test the mic, then go back in to the settings and move the slider to the other end and test again.

What do you mean "active"? I know that the headset is recognized by the Xbox, and I know that I haven't muted myself, but the blue ring around my name does not light up when I talk.