There's Incredibuild (paid), might be worth investigating if it fits your scenario (I have serious doubts it'll work with anything other than basic AOSP due to how lineage's ninja behaves during its early build phase of regenerating scripts from .mk/bp's).
Mind if I ask what's your current record on build time for single device/buildtype combination's systemimage on a single node?
Mind if I ask what's your current record on build time for single device/buildtype combination's systemimage on a single node?