Why not just contribute to Matrix, which is already well established and tries to 'discordify' their ecosystem, too?
Discord - Your place to talk
Discord is a VoIP, instant messaging and digital distribution platform designed for creating communities. You can post memes, stories, questions or advertising. Please tag the posts with: [Advert] [Meme] [Question] [Story] [Other]
Rules
- No Harassment (leads to ban)
- Advertising is allowed, 7 days cooldown (leads to post removal if not followed)
- Flag your post (leads to post removal if not followed)
- Cross posts are allowed from communities under (leads to post removal if not followed)
Gaming Communities
VoIP Communities
In my view, what this ultimately is is a free Discord client. The server is there because I assume the developer liked Discord's API and wanted to be able to self host a server using it, but I imagine the majority of users will be interested in using this client with discord.com.
Keep in mind that "don't use proprietary platform, switch to x/y/z" doesn't account for the unfortunate reality that people may have contacts on that platform and switching wholesale and cutting off contact with those people is an unreasonable tradeoff. While a completely free service would be ideal, using a free client with a non-free service is still an improvement.