Hello @Martine,
We have noticed that your website is loading quickly on the browser, however, you have mentioned that the backend admin panel is running slowly. To address this issue, we suggest that you take the following steps:
1. Delete any unnecessary or disabled themes from the Appearance >> Themes section.
2. Delete any unnecessary or disabled plugins.
3. Delete any unnecessary or draft pages, blocks, products, and posts.
Once these steps have been completed, please clear your browser cache and check back to see if the issue has been resolved. We hope that this will provide the desired results.
Best Regards,
8Theme’s Team