Hi,

There are  different  ways  to  achieve  this.  You can directly update it in the database using query by connecting to postgres.

If you need to do it from the user interface, either you can create a server action that calls python function and update the entire product all at once or you can add that field to the tree view of the products and enable multi editing in the tree view and update.

For Reference:

• https://www.youtube.com/watch?v=TWccA-tVa9E
  
• Add Contextual Action Using Server Action To Ease Your Work In Odoo
• Multi Edit: https://www.youtube.com/watch?v=2BdVAiXja00&t=19s

Also you can check Mass Editing module:  https://apps.odoo.com/apps/modules/14.0/mass_editing/

Thanks