@abmurrow It IS very weirdly untapped, isn't it.
Unfortunately it's not as simple as choosing a language as it's possible to write inefficient code using any language / framework.
For example PieFed (using Python, an interpreted language) uses way way less CPU and RAM than Lemmy (using Rust) while providing more features.
Also some architectures might look efficient on the server because they're making clients do all the work (React) --> ewaste as cheap phones are discarded for being slow.