How to keep deleted files in backup?

I make daily backups on weekdays, limited to 5 backups.
Now I realized, that deleted files are not in the backup anymore. Therefore when I want to restore a file, that was deleted, I habe to do it within 5 days. Furtheron it is lost. Am I right? Or is there a possibility to keep deleted files in the backup (backup the recyble bin??)?

The best approach is to increase or remove the 5 backups limit. Removing deleted files and modifications older than 5 backups back is exactly what this limit does.

I agree with @kees-z – you should implement custom backup retention settings wherein older versions are thinned out on an incremental basis rather than being removed outright after a few days.