Airpods Pro: very bad quality in Headset mode on Windows 10

Why is it then, I can use the same headset on my Android phone and my Macbook and audio quality is just fine but on Windows it's terrible? 

If only you understood how little Windows has to do with Bluetooth ...

Bluetooth is actually a network technology. The network exists between your headset and the Bluetooth adapter in your computer, neither of which come from Microsoft. The driver for your Bluetooth adapter also doesn't come from Microsoft. The codecs also don't come from Microsoft.

Windows' role in all of this is to host the Bluetooth service, for example to provide an interface for the components. The pairing, the connecting, the profiles ... that's all Bluetooth. The stack that provides the functionality ... all Bluetooth.

It took me weeks to figure out how to use my Bluetooth earbuds correctly. Not that the vendor (Soundcore) was much help. Didn't do me any favors. I had to learn this on my own ... how Bluetooth works, how to use it correctly. Now that I understand, my earbuds work fabulously. The sound quality is amazing.

People love to blame Microsoft for everything. And it's not like Microsoft doesn't deserve blame, but not for everything. And not for people who don't understand how Bluetooth operates and how to make it work for you.

pretty much all that is wrong. ever heard of Microsoft Bluetooth Enumerator? that's what makes it possible for a PC without integrated Bluetooth to establish a connection with a Bluetooth device.

When you connect a Bluetooth headset with a microphone to Windows, you’ll see two devices: The standard A2DP high-quality stereo headphones, and the hand-free profile that has worse sound output but also supports sound input.

when you’re just using the headphones as a sound output device, they’re using the A2DP Bluetooth profile, and ideally using AptX for maximum sound quality. When you need the microphone, they’ll use the headset profile or hands-free profile (HSP or HFP). This allows for both recording via the microphone and playback via the headphones, but the headphone sound quality is terrible when using HSP or HFP.

Why is it then, I can use the same headset on my Android phone and my Macbook and audio quality is just fine but on Windows it's terrible? 

If only you understood how little Windows has to do with Bluetooth ...

Bluetooth is actually a network technology. The network exists between your headset and the Bluetooth adapter in your computer, neither of which come from Microsoft. The driver for your Bluetooth adapter also doesn't come from Microsoft. The codecs also don't come from Microsoft.

Windows' role in all of this is to host the Bluetooth service, for example to provide an interface for the components. The pairing, the connecting, the profiles ... that's all Bluetooth. The stack that provides the functionality ... all Bluetooth.

It took me weeks to figure out how to use my Bluetooth earbuds correctly. Not that the vendor (Soundcore) was much help. Didn't do me any favors. I had to learn this on my own ... how Bluetooth works, how to use it correctly. Now that I understand, my earbuds work fabulously. The sound quality is amazing.

People love to blame Microsoft for everything. And it's not like Microsoft doesn't deserve blame, but not for everything. And not for people who don't understand how Bluetooth operates and how to make it work for you.

I apologize, for two reasons:

1- I intended to reply to the OP, not to you.

The OP wrote: "However, in the headset mode ("Airpods Hands-Free AG Audio") sound ... is extremely bad. "

And I answered (correctly) that the headset profile is optimized for voice, and not for other audio.

2- The OP's stated question was about microphone quality ("Any advice to get a better microphone quality?") and my answer was about audio quality.

Not an impressive performance from me. However, I didn't completely miss the mark. Bluetooth quality is a function of Bluetooth and the manufacturer, not Windows. The audio controls in Windows are designed for an on-board sound chip or sound card. They have limited effect on Bluetooth audio.

i'm no expert but you say "Bluetooth quality is a function of Bluetooth and the manufacturer, not Windows". Why is it then, I can use the same headset on my Android phone and my Macbook and audio quality is just fine but on Windows it's terrible? I've had to resort to using the headset in headphone mode and using my webcam's microphone for Teams meetings and my voip phone.

I apologize, for two reasons:

1- I intended to reply to the OP, not to you.

The OP wrote: "However, in the headset mode ("Airpods Hands-Free AG Audio") sound ... is extremely bad. "

And I answered (correctly) that the headset profile is optimized for voice, and not for other audio.

2- The OP's stated question was about microphone quality ("Any advice to get a better microphone quality?") and my answer was about audio quality.

Not an impressive performance from me. However, I didn't completely miss the mark. Bluetooth quality is a function of Bluetooth and the manufacturer, not Windows. The audio controls in Windows are designed for an on-board sound chip or sound card. They have limited effect on Bluetooth audio.