Performance
The sync speed relies on a variety of things, for example, the number of items to be synchronized, the number of images and their sizes, the already existing items in Magento 2, etc.
When debug is active, the files debbug_log_saleslayer_timers_{sync_day} show the total time of the sync, and also the time required for some of the subprocesses needed.
Warning: In the case, the synchronization gets “stuck” or seems not to finish, you can check the cron schedule table by filtering Sales Layer job code ('%saleslayer%). In this link you can have more information on cron logs in Magento: https://devdocs.magento.com/guides/v2.4/config-guide/cli/config-cli-subcommands-cron.html.
If no errors arise, final verification can be done by consulting your Magento catalog.