For several years I was using TTRSS, but this year I moved to a Miniflux instance that I host at home. I couple it with an instance of Wallabag for saving articles for later reading. I like the experience of the Miniflux PWA app better than TTRSS.

Speaking from experience from the last five years, it’s been pretty good for me.

Nextcloud has chat capabilities. Perhaps it might be overkill for chat alone but presumably you also want some collaboration with documents.

By any chance is this from Andrew Tanenbaum?

Minecraft has been suggested here but there’s also Minete St, free/open source version. The experience isn’t exactly the same but the basics are there. Works with PC and Android. You can also run one of the computers as a host and you can do multiplayer. Absolutely no microtransactions.

Budibase.

Hashtags are your friend. It also helps if you have some active posters for the tag. I get good content from following #sciencefiction #coffee and #python.

Start using it more frequently and favor it over GUI apps. For instance, use cd and ls over the file manager. Launch applications I using the command line. Figure out ways to do in the CLI what you used to do using GUI. Over time you should get more comfortable with the environment.