The developer Gunfire Games have acknowledged that they forgot to add the setting to disable VOIP in-game. The users have been complaining about unable to disable in-game voice setting from a few hours. Reddit and Steam community forums have bombarded with frustrated gamers complaining about mic noises.
Tweet from official Twitter handle @Remnant_Game:
We just pushed a hotfix to revert the automatic VOIP activation on PC. It will be re-added, with an option menu UI, in an upcoming build!
— Remnant: From the Ashes (@Remnant_Game) August 21, 2019
Seems like all the issues and troubles will be fixed in an update arriving in a few hours.