WeeChat is really an awesome IRC client. I've been using it daily for years. Before that I was mostly using ERC in Emacs. But WeeChat has a remote client features that makes it possible to have a headless WeeChat running in my server (in a docker container) and I can connect to it from a desktop, web, or android application.

The best web client I know is called Glowing Bear (https://glowing-bear.org/) and it is excellent both on desktop and mobile browser.

The desktop app I sometimes use is KDE's Konversation (which requires an IRC relay rather than a WeeChat relay but WeeChat handles that too). On mobile there is a WeeChat Android app available on F-Droid which works perfectly.