I've used prosemirror enough to have written custom nodes, commands, and custom code around its collaboration model. I got good results with all of this and I don't know any other platform that could have matched it.
The docs are thoughtful. There's an up-front learning curve to understand the architecture. When doing highly customized things, I referred to the source when needed.
For standard rich text, there are a lot of options. Prosemirror shines when you want to build on it as a platform.
"The primary distinguishing characteristic of systems programming when compared to application programming is that application programming aims to produce software which provides services to the user directly (e.g. word processor), whereas systems programming aims to produce software and software platforms which provide services to other software..."
This is what they're referencing with that comment. I don't know that there's a "Japanese" style of Ruby, as much as there is a style that looks and reads more like systems code.
I started using Foam[0] a few years ago, but the more I used it, the more I dropped all the tedious bits, and it became nothing more than a big, evolving markdown repo.
I switched from vscode (back) to vim, and it has worked as well or better than it did before. I follow my own rules. I like the Zettelkasten idea of one idea per card, but if I put more related things in the same .md file, that's OK. I didn't like the flat directory structure, and so I have dirs organized by category. My /bar directory is inside my /cooking directory, and for whatever reason, that makes sense to me. Ripgrep doesn't care, and I always find what I'm looking for.
This markdown hierarchy, that still lives in a repo called "foam", has become indispensable to me.
There's a lot more interesting detail in the wikipedia article, including a full description of the algorithm, and Perlin's own improvement of using simplex noise.
Slack replaces in-person conversations, which have the same deficits, and many of the same benefits. It works best for remote and hybrid teams, where the in-person discussions aren't possible. It can even work well for in-office teams by allowing some collaboration to be more async. It's way better than email for this.
It's terrible for being off the record. All Slack should be considered durable for the employer.