I’m using GDScript myself so don’t take this as an endorsement of these, but Godot lets people build bindings for just about any language. I mean, it’ll limit your options for technical help and limit your options for platforms in some cases but you can do it. Also you’re reliant on yourself or the project maintainer to keep the bindings in 1:1, even the C# which is officially supported isn’t completely 1:1. You can also mix and match as you please, implementing more demanding things in C++ or Go or Rust and others in other languages.
Yeah, sonarr and radarr support some indexers but I ended up just setting up Jackett. They both use those indexers to search, but in different ways. They also don’t do the file downloading, your separate download client does that. They do both track future releases and rename files, but the way that works conceptually for movies and TV shows is pretty different since Movies are singular pieces of media while shows are broken up into seasons and episodes. They work with different data structures and so have to parse and present in different ways.