I have found LibreX/LibreY to be quite good, as long as you use a stable instance

BQN is a newer array based language (similar to APL) where you manipulate arrays with different functions and modifiers and compose the modifiers with more modifiers (combinators). Uiua is the same but instead of combinatorics you have a stack that you can manipulate, so it's a stack based, array oriented language. Here is a nice video about Uiua, and here is a video comparing the two.

To add to others' responses, array-based languages such as APL, BQN and J are very different from most common languages

For getting actual stuff done: Rust For playing around: Uiua or BQN

Simplex chat also has Haskell and Typescript apis iirc

Tbh I'm not sure, it might've also changed during these past 3 years so 🤷‍♂️

Yes, it's more of a decent collection of links to [alleged] issues with matrix, tbf

Here's something you might find interesting "Why not matrix" Alternative onion url

Obligatory link to Why not signal

I've definitely had problems with calls to but I think it's nevertheless the best app out there right now

Afaik yes but it's not as convenient. (You're sending a file, which the recipient downloads, instead of a video as a chat-item-thing). I'm not 100% sure on this though

Well the desktop gui is still in beta (literally less than a week old, iirc). So I wouldn't expect it being on the website until it's fully functional. (And it's a GUI desktop client now)