NetSparkle is a C#, cross-platform, highly-configurable software update framework with pre-built UI for .NET developers compatible with .NET 4.6.2/.NET 6+, WinForms, WPF, and Avalonia; uses Ed25519 signatures. View basic usage here in the README and try the samples for yourself.
I might be missing something, but except for the NetSparkle.csproj I seem to not be able to find any usage.
Edit: was the intention to use it for 25519 verification like eg https://gist.github.com/ezekg/e96ef9c71a8f97b9ffcb487b73bfe248 (instead of Bouncy Castle)?