What is the lightest voice app?

I want to use other apps while talking with the people in the group with the voice app. (Search for something in the browser or play a game) So the question is that the voice chat app is superior in terms of privacy and security, and it does not run slowly when used with other apps I want you to tell me All you need is open source, end-to-end encryption or peer-to-peer encryption, which allows voice chat in groups. (By the way, https://www.privacytools.io/software/voip/ Is there anything that is good here?)