Thank you! GaiaChess actually keeps a PeSTO eval under the hood too: the lower skill levels blend from pure material through PeSTO up to the full NNUE as you climb the ladder. I'll definitely check out Ninny Chess Club, personalities are a great angle. Cheers!
NNUE is an fascinating and throughly modern approach, just like your Rust choice. Ninny Chess Club doesn't need NNUE to crush human opponents, although I considered it. Instead, I went with standard classical chess engine techniques I remember from Shredder and Crafty days. PeSTO keeps it very fast, of course. Hope you give it a go on "Deadly" level vs. Prodigy. Good luck with GaiaChess.