To avoid confusion (as I still see a lot of it across the internet). Personal data includes any information that relates to an identified or identifiable living individual. It doesn’t matter if that email address is a business email address it is still personal data if it includes an individual’s name.
Too many businesses have said they do not process data as they do not send any marketing, processing data isn’t just about any marketing you send. Processing data includes collecting, recording, organising, structuring, storing, modifying, consulting, using, and destroying data. I am assuming you actually have clients, suppliers, customers or referral partners? In that case you process personal data and by law need to have a privacy notice.