Handling large-scale git rebase conflicts in monorepo history

Our team is migrating a legacy monorepo with 8+ years of history into a cleaner branch structure. The rebase involves ~2000 commits across 4 major refactoring periods. We're seeing cascading conflicts where fixing one commit's merge breaks three downstream commits. What strategies have worked for you: interactive rebase with scripted conflict resolution, or a squash-and-rebuild approach? We'd rather preserve individual commit semantics if possible. Currently using git 2.43 with rerere enabled but it's only catching ~40% of recurring patterns.