An asset can look correct in its source application and still fail after import into Three.js. Treat LOD policy as a translation problem between tools, with triangle targets and screen-size thresholds checked on both sides.
For Three.js, keep the LOD policy pass focused on triangle targets, screen-size thresholds, and silhouette quality. Make one controlled change at a time and retain enough evidence for another person to repeat the decision.
Focus the work on triangle targets, screen-size thresholds, and silhouette quality. Apply this LOD policy guidance to the actual Three.js delivery path.