What cloud provider is best for me?
I have a few business clients that are running Synology NAS devices. I am just now migrating to Cloudberry (sorry, hard to write msp360), but in the past, I backed servers up to two NAS devices (each in different data centers) and then used Hyper Backup on the NAS to push to Amazon Glacier since we would really have to have a loss of both NAS devices to require a restore from Glacier. Just remember that a restore from Glacier is very expensive.
I would also look at Wasabi. They have Amazon S3 compatible storage for good price. I have considered using them since they are easier to setup than S3 (which really isn't hard) since S3 is part of the much larger AWS suite and it can be overwhelming to get started if you are new to this.
Getting to your use, I would look at Backblaze or Wasabi for storage and then find a backup program that you can buy once like the Cloudberry backup programs and push data that way. I downloaded trial versions last night and had 4 servers backing up to NAS and cloud by 10pm last night.