If you remember using teamspeak or ventrillo... Their is a FOSS alternative called mumble that works similarly. Its essentially the closest to what you're asking that has both VOIP and other features. Some communities especially mmorpg clans and gaming clans still use it. Idk how popular it is in general though. Discord is supported by huge donations which is why they've been able to dominate, but teamspeak/mumble still exist and essentially are the same thing but less modern.
IRC and Matrix are both IM systems but are alternatives to discord if that's all the functionality you seek. Matrix is also in the fediverse.
I think he isn't the most consistent person when it comes to global politics(russia/china most notably), but it really comes off like he has a ongoing effort to funnel young leftists/liberals/socdems into the ML pipeline. For example, he watches stuff like Second Thought on stream and even went on the deprogram recently. Uses ML terminology whenever appropriate, etc.
That said while not perfect, he IS in the "debate verse" or "reactlord" sections of twitch. unlike Vaush, Keffals, other "leftists" he actively puts China, AES, and THEM TANKIES in a good/neutral light. And anecdotally I have seen members of his community eventually start getting into MLism through that (such as myself). But he will occasionally say/do shit that upsets me as a ML, still I'd recommend him over many others to any liberal friends as a Primer into more Leftist/Marxist content.