I know there's some controversy around DDG, but Loomio is free software and can be self-hosted. I follow some of the loomio team on scuttlebutt, and I'd consider them very ethical. On what basis would you consider them unethical?
Signal is centralized, and my biggest complaint is its requirement that users submit phone numbers. Beyond that, though, they're doing fantastic work in advancing privacy-enhancing technologies. Signal is still the gold standard in many ways.