Hello @Ivanchyk, Vasyl - Welcome to Microsoft Q&A and thanks for reaching out.
If the Network Interface still shows up in your Resource Group, you can check the Network Security Group it was attached to 'main_vmNSG' and review the 'Network Interfaces' tab. If there are any Interfaces in here, you'll need to Dissociate them.
If you don't see that it has an Association with any Network Interface, then you can force Update the Network Interface with Azure CLI, PowerShell, or through Resources.Azure.com
Using Azure Cloud Shell:
CLI Update Network Interface: https://video2.skills-academy.com/en-us/cli/azure/network/nic?view=azure-cli-latest
CLI Update Network Security Group: https://video2.skills-academy.com/en-us/cli/azure/network/nsg?view=azure-cli-latest#az_network_nsg_update
Using Resources.Azure.com, you'll need to find the Network Interface through Subscriptions > (Subscription Name) > resourceGroups > (ResourceGroup Name) > providers > Microsoft.Network > networkInterfaces > (Interface Name)
Edit then PUT to force the resource to update with Azure if it's stuck in a deletion or updating state.
Hope this helps. and please feel free to reach out if you have any further questions.
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