Are you using a bluetooth device? Also there are a few things you can try. First if you have advanced calling turned on than turn it off. It needs a data connection to work so if you have poor service than it will have a bad connection. Also wifi calling, try turning it on if its off, but turn on the option to prefer wifi over cellular connection so it doesnt drop your calls when your cellular connection fluctuates. If that doesnt work than try turning on mono audio, it's for when you are only listening through one speaker. Also see if turning off voice privacy helps and or hearing aid support. Going to research hearing aid support and see specifically what it's for but try that. If that doesnt work you either need a new sim card or your speaker is going out.
When I'm using my buds to speak to people they never can't hear me and/or it sound it muffled. When I listen to music I start to hear weird noises. I don't know where it come or why that happens.
Is there any physical damage to the Galaxy buds? Have you tried resetting the Galaxy buds?
I'm always cleaning them after every used. I also read some where that I have to be careful how I put the buds on my ears because I can be blocking the mic. I make sure that the mic isn't blocked due to my ears.
For resetting the Galaxy buds, open the Galaxy Wear app, and tap the "about buds" tab, the reset option will be at the very bottom of the drop down list. I recommend after this disconnecting bluetooth then reconnecting it again.