Much like the rest of the internet, dedicated forums are becoming less popular as social media is on the rise. A place like UTAforum is still a good place to have in-depth, detailed discussions, or to collect information like in the Resource and Showcase sections. However, in terms of socialization, you're more likely to find people on places like Twitter and Discord.
VocaLounge is a social media platform entirely dedicated to singing synths that's being run by some of the same admins as UTAforum:
https://vocalounge.cafe/
You can also look to platforms where people post the work they've made, like YouTube, NicoNico, Soundcloud, Audiomack, Bandcamp, etc.