So i decided to share it with a couple friends and retro enthusiast communities on Discord. I took a video capture of my engine working, showing the 3d rendering, audio, video, etc with an Xbox->HDMI->USB capture chain. Then attached the file on Discord's input field and posted it (i have a tab with the web UI pretty much constantly open in Firefox). People weren't around at the time but some saw it today and commented while i was sleeping (with my computer off).
Last time i checked, this wouldn't be possible with IRC because:
1. There is no video (or any other file) host on IRC servers.
2. IRC discussions are ephemeral, you either need to be online all the time or setup some sort of proxy that keeps the discussions around while you or others are away (or do what i used to do 15+ years ago - run a terminal-based irc client in a screen session in a VPS :-P).
AFAIK #1 is still impossible and #2 is an optional extension (that i've never seen in real life). Meanwhile i can now connect to a new Discord community and not only not worry about losing any messages while i do other stuff (i often check what people have talk about in Discord since my previous "visit" to be up to date) but also search what people talked about previously - e.g. did anyone brought up some XYZ topic i want to talk about?
IME the above two (also add images and audio to the mix - in two of the communities i'm in there are people who post WIP music they make) are basically 90% of how i see people use Discord: they post something (very often media-based) and very often others see/respond to it in their own leisure much later (in some channels people even live on different timezones so they can't do otherwise).
TBH nowadays if i wanted to set up some community in a self-hosted manned and wanted to stick with open stuff, i'd probably use RocketChat or something like that (Godot uses a self-hosted RocketChat instance that while a bit more janky than Discord, it seems to provide pretty much the same features i mentioned above).