Just stick to signal, matrix can be used the same way but it's a lot more complicated and requires involvement in keeping your backup key safe, otherwise you'll lose every encrypted message! Signal is similar to whatsapp. (which is obviously...a popular app...which should already explain the simplicity of setting it up.)
SearXNG, searches every search engine and regroups them in a single list, alongside the very powerful "bang" variant they use ("!!" is like "!" for ddg, and "!" is to only search with this search engine, ":en" is to choose a specific shortcode language.)
Our VMs are properly synced, it's a known kbin bug but i haven't seen if they solved it already. Once they do fix it i'll update it.