Here’s the way to look at this.
Sh!t always happens in print. Doesn’t matter the software.
Work with your printer to get your maximum expectations.
I’ve done little more than download the trial, and that was years ago. This is a slow-to-adopt program out there on the production side. The software says it supports the major export file formats including the PDF-Xes, and it supports ICC profiles, Pantone and LAB. Since most printers accept PDFs, that’s probably the route you will be taking. Your best bet is to ask for Job Options for exporting.
It’s when you get to wide format stuff, you may need to work a little harder and be a little more vigilant with your print partners. Aside from online gang run printers that’ll accept .jpg format, most of them still want native files to apply profiling properly (you won’t find included ICC profiles for most wide format output. Especially not in-house proprietary ones.) So far I have yet to see Affinity listed as a supported file format at any of my specialty output houses.
Do some due diligence. If you are going to offer print services, scope out or contact those you think you intend to use. Vet vendors ahead for less stress later.
Your goal sounds a bit short for a sustainable freelance service. Business cards, brochures and posters are dime-a-dozen work.
Aim higher. MUCH higher.