Potty Training in an Apartment Before Puppy is Fully Vaccinated

My gf and I will be getting a puppy in the next few months. We feel ready for the most part, however there is one thing that keeps coming to mind. Our breeder and vet have mentioned multiple times to not let our puppy do their business outside at our apartment until they are full vaccinated as our apartment is full of other dogs (we receive puppy at 8 weeks, won’t be fully vaccinated until likely 16 weeks). We have come up with the idea of getting grass mats or turf mats to put on our balcony to potty train until puppy is fully vaccinated. My main concern is the transition from grass mat on balcony to actual grass outside. If anyone has any recommendations or similar stories to share, all is welcome!