IRC is still a thing, and a very popular one at that. I've found that it's a great tool for finding like-minded tech people with relatively less 'noise' than in similar Slack or Discord groups.
I think the technical obstacle to even get onto IRC acts like a great-filter, most the people on there have an interest in it and brain cells to use technology. Unlike Discord where you can just sign up from your mobile phone...
Which networks do you recommend searching around in? I've not really looked hard, but the only ones I've found that are remotely active are filesharing ones.