I love making games, have even had the privilege to do it "for real". I'm looking for some game engine that I can use to make a 2D turnbased rpg game, that would compile for pc and android.
I have tried out lots of engines since a long time, and whats bothering me the most is that windows changes breaking stuff, the engine going paid or cease to exist, or it uses like javascript. So I'm wondering if there would be, today, something you could recommend that is FOSS, 2D, has sound&music maybe a menu interface, effects..., isn't an obscure, old or too new language (like Lua or Rust, sorry!) and works out of the box for PC and Android.
I'm willing to ponder web instead of PC but I'm not willing to go the javascript route :-).
Have you considered Godot?
I don't have any real experience with it, but from what I gather, it's FOSS, seems pretty popular and well supported, definitely supports 2D (also 3D but you don't care), can export to Android or web, as well as PC, and doesn't use any of your "blacklisted" languages. It uses its own python-like script, or you can use C#, and there's extensions for others.
Godot is great for 2D, is FOSS, and it is getting stronger by the minute. Where it doesn't meet your requirements is perhaps that its main language is their own GDScript. it's a really easy language to get started with, but still "obscure". You can, however, use C# to do (I think) anything you could with gdscript.
You can also use C++ to do everything. This is called GDNative. With this you're basically just rewriting / adding to the game engine that is written in C++. Probably harder to get into, especially if you're not too familiar with the language.
I had experience with python so GDScript came naturally, and the documentation is really thorough.
With Godot you can export to Windows/Linux/Web in one click. Exporting to Android just needs like 15 minutes of setting up using the tutorial in the docs, and that becomes single click too.
You can even download the game engine onto your phone and it works the exact same there! Though I wouldn't want to develop on a tiny touch screen lol
VSCode is open source with an asterisk. All the official releases are pumped up with not so open source microsoft parts. I recommend using VSCodium. They take the code and compile & release it so you don't have to do it yourself. You'll have to update it manually, but honestly I had a 1.5 year old release running before I thought to.
The GDScript VSCode(ium) extension is excellent. I've never tried Godot with C#, so I can't say about that extension.
Rust is newish but it's not going anywhere anytime soon. If you've got the chops to work directly in code without a built-in editor, try Bevy. Seriously. It's the future of game dev.