Lack of local storage Scalability for virtual servers (VSI)

We are using different compute and storage resources on IBM Cloud.
Unfortunately SAN based Storage for VSI's as well as Performance/Endurance storage, periodically impacted by high Network utilization, and our Production systems freezing.
That is why we prefer VSI's with local discs for heavily loaded production systems.
Main problem are following:

• We can't increase second local disk on the server without loosing the data.
• Depending on initial VSI flavour we can't extend second local disk outside of flavour limit.
• Image created from VSI with exact local disks sizes for example Primary 100GB + Secondary 100GB, can be deployed only to the same flavour, not possible to choose Primary 100GB + Secondary 200GB.
• Detaching of secondary local disk converting it to SAN based.

Due to limitations above, almost impossible to extend  secondary local disk from 100 to 200 GB without of full data loss.

What we need:

We need functionality on the portal or API which simplify secondary local storage increase, for example ability to order from image VSI with local disks which capacity higher then initial size on VM used for image creation.