The Plugin "GP Premium"

Hi there,

You can do the update manually.

Please check our installation article. The procedure to update is exactly the same. :)
https://docs.generatepress.com/article/installing-gp-premium/

Does this erase all the custom work Ive already done to the site? Will it erase all the design elements?

Hi there,

manually updating the Plugin will note remove / change / delete any customizations, elements or anything else you have worked on ... all of that is saved in your database.

Although theres never been an issue - its good housekeeping to do regular backups on your site :)