Kotlin with Vert.x or Spring Boot depending how complicated things are in the backend. Spring can boost your productivity if you really need it. Vert.x gives you more control, but you will have to write more code. Java is also an option, but Kotlin is simply nicer.

When it comes to FE, I don't touch that anymore. I did some react and old angular in the past, but it was more like an obligation... I don't "feel" the community, or how complicated things have become.

For programs that are closer to the hardware or operating system, I feel quite comfortable in C (not C++).

For scripting, data visualization, and anything math related I use python. I usually end up having one big script, terrible written that works.

When it comes to databases, I pick mariadb because I have the biggest experience with it and it didn't disappoint me. From the NoSQL land I've tried the most popular ones, and I had good interreactions with redis, and the elk stack.

I've tried to love Go and Rust... I still try, because some companies I follow and have interesting projects are using them. But it's more like a long term goal to learn rust.

I believe my stack is boring, if not boring conservatory.