One of the limitations of a WordPress.com website, or a “hosted website”, is that you have a limited amount of control over the website. These hosted platforms have their benefits. I have built several client websites using WordPress.com instead of WordPress.org for a variety of reasons.
Although there is a zero-maintenance factor with these websites, the downside is you can’t install any backup plugins.
However, there is an option to manually export a backup of all your content!