Sound output device randomly disappears

Here's my problem:

I use Apple Music to listen to music. I usually have my headphones (Beats X: bluetooth), but since I'm home office I just listen to music through my speakers. When I stopped using my headphones, the music would randomly stop and continue in 1-2 seconds.

First I thought it was an issue with the internet, which makes sense since I'm working from home & didn't have the same problem when I was at work.

However, then I noticed that that the sound icon in the top bar goes from this:

to this:

So I started googling for problems with Macbooks randomly muting themselves. I found nothing about such problem.

Then I noticed that in a Skype call, Skype would say that I have no microphone/speaker hardware, which made me open System Preferences > Sound and stare at my computer (with music on) for 5 minutes to see what happens.

It turns out that both input & output devices (built-in) disappear from the lists of available devices for input & output.

As I mentioned it doesn't only happen while listening to music in Apple Music, same issue appears in Skype calls, while watching Youtube videos, etc.

Any help is appreciated! Thank you & stay safe.