Hi,
There appears to be a bug in portal where it isn't showing available Intel options.
As a test, please use below powershell commands in Azure Cloud Shell to create Azure Database for PostgreSQL Flexible server in East US and East US 2 regions. When finished you should have two Standard_D2s_v3 servers, one in East US and the other in East US 2.
$dbEastus = New-AzPostgreSqlFlexibleServer -Location eastus
$dbEastus
$dbEastus2 = New-AzPostgreSqlFlexibleServer -Location eastus2
$dbEastus2
Once the above two commands are finished, please navigate to the servers in the portal and click on Compute + storage blade. Click the Compute size dropdown and notice all the options available.
IMPORTANT: When finished testing, make sure to delete the two resource groups that were automatically created above so that charges do not continue to accrue.
Please click Accept Answer and upvote if the above was helpful.
Thanks.
-TP