caleb since the prefix is also part of index and key names, it's a bit risky to edit it on a production server.
The best solution might be to use search and replace on an SQL file export of your database, before importing the backup back into a new empty database. A visual inspection of the whole file might be required to make sure nothing was accidentally broken. Be careful of not replacing text inside of user-generated content like comments and bio.
There is still a slight risk of messing up if an extension used some custom logic to name its columns, where it might fail if it is ever uninstalled, or if something is incorrectly shortened when it shouldn't have been.
The absolute safest solution would be to make a data-only export of the production database, rename all tables in the export, then create a new Flarum installation with the same extensions but no prefix, then export that new database structure-only. Then merge the two backups into a new prefixless database. That would ensure all tables have been re-created from scratch with everything correctly named.