Stop running flutter clean for every flavor — it wipes caches and kills build speed. Reuse Gradle (~/.gradle) and Pub (~/.pub-cache) caches across jobs, and enable -Dorg.gradle.caching=true. Build only changed flavors (via git diff) instead of all 100 every time, and parallelize builds across agents. Use appbundle/--split-per-abi to reduce artifact size, and keep only final signed outputs. Caching + selective builds + parallelization will cut build times drastically.