Massage practice seeks practice management

I am looking for a complete practice management system for my massage practice. Initially, it will be a massage practice, but later it will become a naturopathic practice.

The solution should meet the following requirements:

• Appointment calendar – ideally also available online for patients.
• Appointment scheduling.
• Billing
• Complete documentation of the treatment.
• Billing according to the relevant fee schedule and in compliance with the GDPR.
• If possible, direct connection to tax accounting and my tax advisor.

One software workstation is planned. Work will be done on a Windows PC or iPad.