I use Azure Storage Accounts - costs about $0.76 for 37GB per month. I’m still using an old Synology DS918+ but it backs up automatically to the Storage account every day. If you go that route, be sure to edit the network configuration, set it to only access from “selected networks”, and then put in your home IP or CIDR. Use that and an access token so you have at least two controls preventing the internet from accessing it.