Report viable options for IT data destruction

I need a report targeted at an experienced IT Security Professional on viable options for data destruction (or as close as possible) in a variety of general situations using SaaS / PaaS / IaaS / on prem disks / encrypted databases at database level / encrypted databases at row level.

The report should provide insight into the challenges accociated with applying particular removal methods to particular situations and include quotes or paraphrasing from GDPR handbooks, Data Protection Act, NIST, CSA, ISO27001 type "organisations" to whilst sighting them to convey how the industry solves these issues. Where an option is viable the advantages and disadvantages should be articulated including any risks of the data being recovered and any mitigations.  Where an option is not viable the rational should be conveyed. Where there are no good options alternatives should be proposed such as removing access to data and speculation over how the Information Commissioner would feel about that and any compensating controls.

I expect the format to be similar to:
1)Introduction to talk about why data removal is required with particular emphasis on GDPR and broadly why things are more complicated scenarios where you can't just point at a disk and crush it.

2) Different data environments an organisation might encounter SaaS / PaaS / IaaS / on prem disks / backup media/ encrypted databases at database level / encrypted databases at row level / unencrypted databases / general unencrypted data and a brief description of those scenarios.

3) Different methods of data removal and a brief description of those methods.

4) Reviewing how applicable and viable different data removal methods (e.g. Crypto shreding / DoD wiping etc) are in each data environment using different "deletion" scenarios:
A) Exiting or decommissioning the above.
B) Removing single records from the above (not applicable for all environments).

5) Reach conclusions over the best way to conform to GDPR Article 5 and generally reduce the risk of ineffective / unreliable data removal in each environment / scenario.

I am expecting the report to be 5 pages approximately in size 11 font plus diagrams if you see fit to add them. (I don't mind bigger or smaller - it's the content and thought process that counts).