In total, there are three ways to transfer data. The first one is the most commonplace - using the PlayStation Plus cloud service. Those who do not pay for a subscription are offered to use a LAN / Wi-Fi cable or simply drag and drop the save using an external hard drive/flash drive.
The developers emphasize that problems should not arise with the restoration of progress. But they clarify that all of the above tricks will only work if gamers use the same account on PS4 and PS5.