I want to strongly advocate for discord server too! (is there already a server?)
Communicating on IRC feels like sending FAX messages

I tried a few times, nobody ever answere me there. There is no chat history..
If u want to ask a single question about game - creating a forum topic feels cumbersome and the reply timer might be in days or weeks.
I get that the game is strongly tied to an IRC and migrating to (or setting up) something else has a lot of friction with it...
I'm very gratefull for BTPro still functioning all these years (I played few years back for a while) and It's super awesome that there is still a community of players enjoying OpenTTD. I'd like to help that community grow/keep rather than watching it die out. Also I would be more than happy to share some of my acquired gaming knowledge to newer players and it's simple not possible to do it here.
So here is my offer:
I can help someone (admin or moderators) to setup a discord server including channels, roles and right, bots etc.
---- OR ----
Make it myself and then grant those people roles there.
I've experimented with discord bot and I am able to setup a two-way communiaction between irc<->discord
which can help OGs use their prefered communication style
TL;DR;
If there is a desire to have a discord server, but setting it up is too much time - I'm your man and I can help. Just let me know and we can discuss the details and preferences.
PS: While writing this message the forum froze and I had to do it once again.. iirc this was happening to me 6years ago too :/