Offer a real time slot, because plenty of buyers here would rather book than call
A metro full of recent arrivals with no referral network produces a lot of people who will choose the company that lets them finish the job on screen.
Online booking does not have to be a full scheduling integration. Even a short request flow that offers two or three concrete windows and confirms by text beats a contact form that promises somebody will be in touch.
Keep the phone number equally prominent. Older housing stock, complicated jobs and property managers all still call. The mistake is forcing everyone down one path.
If you cannot commit to a window on the site, say what actually happens next and how fast. A sentence like a dispatcher will text you two options within fifteen minutes is a promise you can keep, and it converts better than silence.
Whatever you promise, instrument it. If the site says fifteen minutes and the real answer is the next afternoon, you have built a machine for generating bad reviews.