I would second Elixir. Either that or Rust. Sure both are popular, but for good reason.
They are completely different from the languages you use.
You will be introduced to new paradigms.
As a person who used the same stack as you (albeit typescript instead of JavaScript), I think it would be a waste of time to learn C#. It is so close to Java, and learning it may make you hate having to use Java, because it seems a bit better put together. Even though it runs on Linux, and is a good language, I don’t think there is ever a reason to chose it over Java, because M$.
Here is a real world example of someone doing some reverse engineering of compiled code. Might help you understand what is possible, and some of the processes. https://nee.lv/2021/02/28/How-I-cut-GTA-Online-loading-times-by-70/
Each electron app has its own Chromium runtime. With the prevalence of electron apps, the result is multiple instances of chromium running on your machine. Chromium isn’t light weight. On top of that, there is the philosophical aspect. Do we really need to be shipping an entire browser for the purpose of creating a UI? That being said I understand why so many electron apps are created. HTML/JS/CSS are powerful and easy to use (IMO) and cross platform. I just try to avoid them and use alternatives to electron.
For real. Wouldn’t even consider it
I think there is some info missing. You’re using SSH to access the server where you are running the docker image? Why does your server have X server installed?
I have no experience running Lemmy. It could be the Lemmy instance includes X server to run some kind of GUI? Seems strange.