Interesting Telegram has both a native (Swift/Obj-C not sure which) and an cross-platform-codebase app for macOS. The former is called Telegram for macOS and the latter Telegram Desktop. Both are on the app store even. So it would actually be a very good case to compare performance, etc. The native one presumably shares a lot of code with iOS which is probably why it exists at all, and it supports secret chats. Otherwise they have similar but slightly different design and features.

However, I think the Telegram Desktop client is not Electron either, it is just regular C++ compiled on different systems.