Hi @Mersys System Welcome to the Atlassian Community!
As per this document "Site import in Confluence Cloud is restricted to a maximum 200 megabytes for the uncompressed XML files inside the backup zip file. This is the 'data size' of the backup. There's no limit to the file size and number of attachments.".
It is possible that your 'data size' might be less and the attachments size is huge. You can give a try importing it in confluence cloud and it will inform you if the backup data is too large. You will also find steps if the size limit is exceeded on the same document.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.