These are my personal solutions to the advent-of-code procrastination shenanigans. Instead of having multiple repositories I prefer to have them all in one.
Every year I might switch and try out a different language, that's why each year has its own root and tooling.
For setting up reproducible tooling and developer environments I use Nix and my personal tsandrini/practical-flakes-template template which you can find in every year. This makes it fairly easy to set up radically different tooling every year.