In the following year, I'll be focusing on working with different backend languages and trying to stray away from using the typical MERN stack web app. Specifically, I am looking at languages like Elixir, Rust, and Go because of their ability to be multi-threaded and typed.
I think that Figma's rendering engine is really cool and what they have been able to pull off by creating such a strong multiplatform experience is a clear example of the future of web apps.
Discord is another company that I think is raising the bar of what a service in general is able to do. They handle users on a multitude of platforms speaking concurrently with each other and throughout my use of the service I've never experienced any issues.