Rosetta support in linux-builder on macOS is upstream in nixpkgs now. Add 2 lines of config to your nix-darwin config to build x86_64-linux with pretty good performance on your Mac:
LLM disclaimer: Image generated with AI. Text human-written. Code in nixpkgs PR human-written. Mentioned vmm tool written with LLM support. (If you don’t like something here, please talk to me like with a human who has feelings like you do. Point out what could be done better. Please don’t call my work “AI slop” because it contains AI pieces.)