@Fahad Noaman , Please try running this query in Azure resource graph explorer,
kusto Query to get details of VNETs and its Address space.

Fahad Noaman
131
Reputation points
Query from Kusto to get details of VNETs and its Address space on all the subcribtion.
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suvasara-MSFT 9,891 Reputation points
2021-09-15T20:17:39.487+00:00
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suvasara-MSFT 9,891 Reputation points
2021-09-14T15:28:41.823+00:00 @Fahad Noaman , Try this,
resources | where type == "microsoft.network/virtualnetworks" | extend AddressSpace_AddressPrefixes = tostring(properties.['addressSpace'].['addressPrefixes'])
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