What is the difference of Handsfree Head Unit(HFP) between A2DP?

I am using wemeet-bin for online classes. I found that the sound of Linux version is very awful, but on Windows it is good. There is much grrrr sound. And I found that when I change my bluetooth headphone to HFP from default A2DP, it will be much better.


I changed to pipewire from this solution:

Now I use A2DP+AAC, it is perfect like on Windows

Here is a comparison and explanation from Philips Audio for different profiles:

If the headset is mono or stereo, there will be a difference depending if using the proper profile or not.