A comprehensive "Guide to Family History in the Bremen State Archive" can be downloaded at the Staatsarchiv Bremen at this link: https://www.staatsarchiv.bremen.de/service/researching-tools-15435/. It is a wonderful guide, in English, to the many genealogical sources available at the Archive, including a comprehensive table of available church records for Bremen compiled by Viktor Pordzik. Many of these sources are online with links to indexes as well as the original records.
DIE MAUS Gesellschaft für Familienforschung e.V., Bremen
https://die-maus-bremen.info/index.php?id=1&L=0
Index and link to images for Bremen Civil registration records are available at this website: Die Maus Bremen
Meta search to find names: Die Maus Bremen
Archive website with images: https://www.arcinsys.niedersachsen.de/arcinsys/detailAction.action?detailid=v8580632
Source of information: Archion forum: https://www.archion.de/en/forum/threads/meilenstein-f%C3%BCr-die-genealogie-%E2%80%93-bremische-personenstandsregister-zivilstandsregister-und-stammtafeln-online.16255/
Military records are available on Ancestry.com. These include Restanten lists which sometimes list emigrants who went to America without military permission. See this collection: https://www.ancestry.com/search/collections/60899/
How to find church books in the Bremen state archives: https://www.youtube.com/watch?v=k-4sHaTEz7A/
Bremen Bürgerbücher: https://die-maus-bremen.info/fileadmin/pdf_docs/blaetter_der_1-12/Band%2001%20Ergaenzung%201925.pdf
Ortssippenbuch Bremerhaven: https://ofb.genealogy.net/bremerhaven/?lang=de