A client of mine once explicitly asked to communicate via Wire [1] which is pretty similar to Skype but E2E encrypted. It was launched by a Skype co-founder, is easy to use and has a pleasant interface. And it's open source. I can't really tell if the product really does what it's advertising, perhaps someone with more expertise could chime in on that. I got stuck on it and I'm considering ditching Skype altogether for it. Perhaps not the solution you were looking for but interesting nonetheless!

[1] - https://wire.com/en/