V5 and 7 are two completely different versions, each with their own set of database tables.. As you might have noticed they can co-exist on the same site.
I reccommend to update your v5 to the latest version and then migrate your data to v7. https://docs.acymailing.com/setup/migration
Once you have migrated your data you can uninstall your v5 and its plugins.
In case you want to continue with v5 oon Joomla 4 you need to update v5 to its latest version, which currently is 5.11.2.