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Nheko is quite good too, I mostly use gomuks and nheko, though I regularly fire up neochat too :)

Not sure which are packaged, though. You usually want the latest goodies, so AUR/flatpak it is for me.

NeoChat only needs Kirigami (for the UI), KCoreAddons (for the about screen), KNotifications/KWindowSystem (for the notifications), KConfig (for the configuration). Probably the KNotifications dependency could be made optional without too much ifdef but I'm not sure if this is something users want.

If you use Weechat for IRC, there is a Matrix bridge plugin that would allow you to connect to Matrix from the command line.