I create invoicing software for home businesses. My users may export and back up their data.
Valentina for Raspberry Pi OS makes it possible.
Ultra Fast Local Database Storage and Reporting on Raspberry Pi OS
ValentinaDB ADK and Valentina Reports ADK are available on selected development platforms for deployment on Raspbery Pi OS. The following solutions support unlimited, royalty free deployment.
ADKs ("Application Developer Kits") are also available on different versions of Windows and macOS as well. The Client portion of the ADKs are all free for use with Valentina Server.
ADKs are licensed by development platform and operating system, and not by hardware platform. This means the ADKs you deploy on Raspberry Pi OS (as a Linux derivative) also work for deployment on other supported Linux ARM64 and Linux x86 platforms.