This list is not meant to say "this is the best language for this", but rather, "you'll have an interesting learning experience with this":

- web backend => ruby (with RoR)

- web frontend => JS

- network => go

- gui => dart

- perf sensitive => rust

- mac os only => swift

- windows only => F#

- cli scripting => nim

- embed => zig

- new perspective on programming => lisp

- want to experience clean theoretical concept => haskell

- need super reliable service => erlang

- lots of data processing => julia

- lots of number exploration => j

- video game => C# (with unity)

And I say this as someone who would likely use Python for 80% of those.