I’ve actually managed to evade the need to jump on board to Matrix chat and mostly stuck to IRC since the 90s. Yes, I know, I’m old school. What can I say?
I now want to explore the matrix system, and I’m learning that there are plenty of apps to use similar to IRC.
So I ask you which Linux app and Android apps would you recommend? I don’t plan on self-hosting any servers. I just want to join already existing communities such as the EOS one 
I use neochat. It is simple and lightweight.
Oh, you’re talking about the KDE application. Didn’t know it was a matrix client. What do you use on mobile? I don’t see Neochat in F-Droid
I don’t use a mobile client. I am not all that active.
On Android: Element (F-Droid)
On Linux: Element web ( If you have a Chromium-based browser, you could install it as web app)
I guess you could install that if you want but I only use the web interface in a browser.
As I mentioned, if you have Chromium for example you could navigate to https://app.element.io/.
You will either get an option in the URL bar to install it as web app, or you go into the settings and create a shortcut for it to be launched as a window.
I’ll probably just go with the AUR, since I’m a Firefox user.
The layout looks like discord 
In Android I use Element from the F-Droid Store
On the desktop I use app.element.io in a separate container. I use Firefox-Multi-Accont-Countainers extension and have assigned a separate container to each page that requires my login types, such as bank, mail, EOS forum, element and so on
I proceed in a similar way to @pebcak
cmatrix with lolcat for pretty colors 
i use standard element client 
BLOOOOOOOOOOOAAAAAAAT!!!1111111
P.S. Latest version:
