The Joomla version is 5.4.1.

The JCH Optimize component was installed on the site. I read that the issue might be related to it, so I first uninstalled that component and then attempted to update SPPB.

but I still couldn't update it

Hi there!

Thank you for bringing this to our attention, and I sincerely apologize for the inconvenience caused.

To assist you more effectively, may I kindly request temporary administrative access to your site? This will allow me to thoroughly investigate and resolve the issue for you.

Before sharing the credentials, I strongly recommend taking a complete backup of your site to ensure all data remains secure.

Looking forward to your response.

Best regards

Please reinstall sp page builder and check if that solve the issue.