Recommended backup SharePoint services or methods?

We've "lost" files here and there (people probably accidentally deleting or moving files/folder that we were never able to recover from the SharePoint site recycle bin or secondary bin) in our small 100-person non-profit that has everything in 365 SharePoint groups. One time when looking for help on reddit, a redditor mentioned "just restore your backups, it's easy." As the most IT curious person in our org who manages our 365, I don't actually know what he's talking about. Are backups built in? Do people with 365 usually purchase a 3rd party service/add-on that automates backups to help in situations when something gets deleted accidentally or lost one way or another? We recently got some Azure space. Are there good options there?

Any recommended 3rd party groups or advice at all is greatly appreciated. Thank you all in advance for helping me start getting up to speed.