Internal speakers not showing up

I have a Macbook Air 2017 running Monterey. When I try to change the volume, it just shows 🚫. I look into the sound settings but my internal speakers do not show up as an option.

When I turn it on, it does not have the startup sound.

This has been going on for at least two months now. So far, I’ve tried:

• Updating my MacOs (to the latest Monterey version)
• Restarting my Macbook
• Resetting NVRAM (multiple times)
• Resetting the SMC (multiple times as well)
• Killing the core audio (both through the terminal and activity monitor)
• Booting into Safe Mode
• Creating a new admin profile to check if sounds work over there
• Plugging and unplugging headphones. A few weeks ago my laptop can detect the headphones (although it didn’t fix the internal speakers issue) but now it just does not detect it at all. Bluetooth earphones still work though.
• Checking if there’s anything wrong with the audio jack. I used a toothpick to poke around but found nothing. No red light either.
• Running Apple Hardware Test. It says no issues were found
• Opening my Mac anyway. I tried to check if anything was burnt or broken or something, but I found nothing visibly wrong. I’m not very familiar with Apple hardware though so I don’t exactly know how to identify problems with the components.
• Erasing my hard disk and downgrading to a different MacOs using a bootable disk. Internal speakers are still not found.
• Retrieving my files (and MacOs) using the Time Machine. Did not expect much from this.

I’m running out of options. Is there anything else I can possibly try to do before taking this device for repair? Or is there any way I could figure out what’s wrong with the hardware and replace it myself?

Please help. Thank you.