Use Azure Bastion with VNet peering
The Microsoft PaaS "Azure Bastion" is a popular service to make your Azure networks more secure. However, until now there was a drastic limit. Azure Bastion could only be used in the same VNet. VMs in a peered network could not be accessed via Bastion. This circumstance pushes up the costs, because with a hub-and-spoke topology you have to place a bastion in each VNet. But these times are over. Use Azure Bastion with VNet peering (since 05.11.2020 in preview).