Applying locks can lead to unexpected results because some operations that don't seem to modify the resource actually require actions that are blocked by the lock. Locks are inherited to all of its resources if it applies on resource group level.
Upload a blob to storageaccount1 is possible if we have readonly lock on RG1 since we are trying to modify the data not resource properties.
When a R/O lock is put on a resource, you lock it's properties not the resource. So while a read only lock is present on a storage account(inherited from a resource group), a file can still be uploaded to the already existing container of a storage account.

Incorrect Answers:
Generate an automation script for RG1 is NOT possible in read only mode.
A read-only lock on a storage account prevents all users from listing the keys. The list keys operation is handled through a POST request because the returned keys are available for write operations. When we tried to read the Access Key of the Storage Account , get the below message.
Access blocked The resource is locked Cannot access the data plane because of a read lock on the resource or its parent.
A read-only lock on a resource group that contains a virtual machine prevents all users from starting or restarting the virtual machine. These operations require a POST request.
Reference:
https://docs.microsoft.com/en-us/azure/azure-resource-manager/management/lock-resources