I would definitely create a URL inventory before touching the new structure. I usually divide pages into three groups: URLs that should remain unchanged, URLs that need a logical replacement, and pages that can be retired because they no longer serve a purpose. Then I create a redirect table with the old address, destination, status, and reason for the change. Codelibry specifically treats URL mapping and redirects as part of its migration process, so I would consider that approach rather than leaving redirects until the final day. Their migration service also emphasizes retaining important metadata and testing the resulting site before launch. I would read
https://codelibry.com/services/wordpress-migration/ for more detail. Before going live, I would test the redirect list in a staging environment, check internal links, inspect important landing pages manually, and crawl the new site for unexpected 404 responses. I would also keep the old site available temporarily in case something needs to be checked.