Is is possible to configure the the Veeam Backup Server as Offhost Backup Proxy(same physical machine)?
The role of off-host proxy can be assigned to physical machine with Hyper-V role enabled. The other requirements are covered here
. As to the backup server, it can be installed on top of that machine.
Is a advanced deployment necessary at this size of infrastructure?
It's up to you to decide. With the onhost proxy all of necessary VM processing operations will be performed directly on the source Hyper-V host. While off-host one allows you to take this workload away to a dedicated physical machine (“offhost proxy”). So, if you source host is deprived of resources or you don't want to overload it, then, use offhost proxy.
Anyway, the best idea might be to test onhost proxy first and see whether it answers your requirements. If not, proceed to offhost proxy deployment.