What is the best way to cloud save IAP items bought using virtual currency?

My app will be using virtual currency to buy in app items. I can handle the buying of the virtual currency using the Google and Apple IAP services.

However, I would like to ensure that any items bought using virtual currency is saved on a server and the user should be able to transfer the items that are bought when re-installing the app or switc$$anonymous$$ng device.

What is the best way to ac$$anonymous$$eve t$$anonymous$$s? I unfortunately do not have the time to write and maintain my own server to store the purchases. I was t$$anonymous$$nking of going ahead with PlayFab or GameSparks for saving the items in the cloud. Any suggestions/advise will be helpful.

Can t$$anonymous$$s be ac$$anonymous$$eved without the user setting up an account on a cloud service like PlayFab or Firebase?