Construction planning company (in the process of being established) seeks complete craftsman solution

I am looking for project management software or a complete solution for tradespeople for my construction planning service, which is currently being set up.

The software should meet the following requirements:

• Quotation creation
• Order confirmation
• Invoice creation
• Support with dunning
• Post-calculation
• Creation of calculation modules including pricing
• Interface to the tax office (DATEV)
• Cloud solution - at least in the foreseeable future - desirable
• Monthly payment preferred

Initially, one software workstation is planned for the company founder, with the option of expanding to up to five workstations later if necessary.