If there aren’t any CSS classes with the names of those spans, then there is no need to remove them, as they won’t change the visual look of the output.
But there are Search and Replace plugins that will do that for you. (My favorite is “Search and Replace Plugin”. ) You would just need to be very careful in how you specify the search string, So a backup of the database is really important.
If you want to remove all ‘spans’, for example, there are regex expressions that you can use. They are quite specific, and regex is not easy, but there are lots of googles (or bings or ducks) to help you with the process.
You can also use phpMyAdmin to directly interface with the database. That requires a bit more experience; you didn’t mention your level of experience.
And again, backups of the database before you start is important. You might even clone the site to ‘practice’.