Dunno if Gitter is better than IRC as I have only used for help and support (for me) but Gitter was far easier to use than IRC. Just Login and start chatting.
I don't think IRC is going anywhere either... We just have alternatives to freenode now in Gitter
I don't know if this still holds true. I've been a IRC user for ~20 years and the current state is a fraction of the fraction of it was once before. Compared with the entire internet, it can already be considered irrelevant, imo.
(You'd think with all the Wordpress one-click-installs that this would exists, but I can't find any yet at least.)
See https://opensource.com/article/17/5/introducing-riot-IRC, https://about.riot.im/ and https://matrix.org/.
I’m not sure if quassel-irssi is also included, but that and quassel-rest-search should be easy to add.