Painting company seeks business software

I am looking for new business software for my one-man painting company.

I have the following requirements for the software:

• Quotation
• Discount
• Invoice (can also be sent by email)
• (Post-)calculation
• Measurement (mobile)
• Calendar with Outlook connection
• Connection to MS Office
• Open Item management
• Outgoing and incoming invoice management
• Sales lists
• Compliance with the principles of proper management and storage of books, records, and documents in electronic form, as well as data access
• App connection would be nice
• Interface to financial accounting
• Interface or connection to manufacturers (e.g., Brillux, Mega)

One software workstation is planned.