Backup mailbox configuration only, but no emails
In the server backup settings, there should be a setting such as backing up all the settings of the e-mail addresses and not backing up the e-mails in the mail accounts. There is no need to backup mails on servers that mostly use pop3, and because this setting is not available, backup sizes are too large.
In automatic and manual server and subscription backups you can uncheck the "mail messages" box to exclude messages in mail boxes. This will not backup the messages but will still backup the configuration of the mailbox. The mailbox configuration can be restored afterwards by restoring the mailbox. Only the configuration will be restored in that case, not the content of the mailbox.
-- PD