I'm speaking from experience here, having tried to implement M:N and abandoning it in favor of 1:1, which yielded better performance. Can M:N yield better performance than 1:1? Sure, in some circumstances. But I think that, ideally, we should be striving for 1:1 everywhere.
The point of M:N schemes isn't to achieve better performance but rather to achieve higher scaling.
That said, I'm not sure such thing exists. Just the memory overhead some common libraries impose on connections is enough to fill some 32GB.
Heck, you can probably handle a million connections using PHP(with swoole).
Just to clarify : my knowledge on this is pretty deep so the only reason I didn't say "they exist" is that I don't personally have one in my DC (I've only managed up to 200k live connections). I know people very well who do. But yes of course the application would be written in some efficient language fit for the purpose like C, Rust, Go, Erlang. Probably not Java.
Also 32GB is not much memory these days.