Freelance accountant seeks software for backup, data backup, and data protection

As a self-employed accountant in southern Germany, I am looking for software for backup, data backup, and data protection for my office. A very high level of data security must be guaranteed, as the data in question is sensitive accounting data. I work with a wired connection (network, USB). I have a DSL connection.

The software must meet the following requirements:

• Backup
• Data backup
• Data protection
• Email archiving – including from external mailboxes
• Structuring during archiving
• A second laptop must then be connected to the single workstation, which actually requires a tower
• Local or web-based (if web-based, then please a data center in Germany)

One software workstation and an additional laptop or PC are planned, as well as a tablet connection.