A serious question: what kind of stack should I choose so I can run a web backend installing no deps whatsoever? I know that Perl works on ubuntu out of the box. Anything else? Maybe Python?
Also, what can be used to replace a reverse proxy like nginx? And what kind of database is available out of the box?

I would replace nginx with caddy. Https out of the box. Nginx-like config. Add (sub)domain - reboot process and happiness is there.

Python backend can be ran without any (python)dependency using the Built-in httpserver.

Sqlite3 is Built-in into python.

What do depencies really matter since docker exists?

My favorite setup for an API would be python, dataset(sql(ite)ORM), aiohttp. You can write performantic stuff in a few lines. Can be that fastapi is maybe even better since it comes with swagger, but I don't have much experience in that

Honestly, if your backend is solely for database queries I would recommend just use supabase or pocket host, you can just write custom rules/filters on incoming requests. Unless you need to access another api in backend other than modifying the database

@retoor not even a bad stack ngl, I'm writing it down for future use

Python is what I've used, but I've heard Go is nice for backend. I've been experimenting with the language I want to try to see what some web apps would be like with it.

What do you need the reverse proxy to do?
TLS termination? Otherwise you wouldn't need a reverse proxy (if you want to keep it simple).

@retoor for example https://0x0.st is written with flask
https://git.0x0.st/mia/0x0

And /dev/null is webscale
https://youtube.com/watch/...

@j0n4s flask is nice alternative for aiohttp. I do not recommend aiohttp for the aio-part but for application structure. The structure is perfect. Flask's blueprint stuff is for men who like men. It's not straight forward

Go