Bitwarden already stores a local copy on all devices you have it installed. Just make sure you load up those devices from time to time... And guess what, you are probaly already doing that with your phone and laptop (which actually contains generally 2 copies, 1 on your actual client and another for the browser extension. Add a third device for good measure and... Oh, you also have a backup on bitwarden.com, this thing literally backups itself everywhere!