Yes you could. You could create a VPN connection between your site and Azure. Then spin up a VM in the cloud and attach a large disk to it to use a a Veeam repository. You'd have to do some calculations as to cost though, this can get pricey real quick.
Alternatively, we have a device called a NetApp AltaVault. This presents its self as a Veeam repository where you write copy jobs to. Then it automatically dedupe's, compresses and encrypts the backups and streams those copy jobs to Azure an BLOB. You set retention policies on the AltaVault as to how long you want it to keep data locally on the device VS just in the cloud. Veeam is unaware the backups are ever purged from the device and left only in the cloud. If you need to restore a backup that is only in Azure, you can pre-populate ( pull the backup back down from Azure) before you try and restore so Veeam doesn't time out while the backup file is being downloaded. We have a physical device but they make virtual devices that can use existing compute and storage. We have ~170TB logical on the AltaVault but after dedupe and compression it is only around 12TB or $100 a month in Azure dollars.
Keep in mind that Azure Blob will be for long term archival.
As far as replicating to Azure from Veeam, I don't believe that exists. You can restore to azure from Veeam however. See this page for more detail: https://www.veeam.com/cloud-direct-restore-azure.html
Hope this helps.