Hi,
Thank you for the details.
Since the SP Page Builder update installs successfully when uploaded manually, but fails through Joomla's Update Manager, it may be related to a security layer blocking the update request.
Could you please check whether ModSecurity, a Web Application Firewall (WAF), or any other server-level security/firewall rules are enabled on your hosting? These can sometimes block Joomla's update request or prevent the update package from being downloaded correctly.
If possible, please temporarily check/disable the relevant security rule or ask your hosting provider to check the server logs for blocked requests when you try to update SP Page Builder through Joomla.
Kind regards,