Quote from the updated guidance :
"We're taking action to ensure the continued operation of deployed VPN gateways that use Basic SKU public IP addresses until the retirement of Basic IP in September 2025. Before this retirement, we'll provide customers with a migration path from Basic to Standard IP.
However, Basic SKU public IP addresses are being phased out. Going forward, when you create a VPN gateway, you must use the Standard SKU public IP address. You can find details on the retirement of Basic SKU public IP addresses in the Azure Updates announcement."
https://learn.microsoft.com/en-us/azure/virtual-network/ip-services/public-ip-basic-upgrade-guidance