The Computed Pattern in NoSQL is utilized when we have data that needs to be computed repeatedly and optimise performance of our app, and is also used when data is reads exceeeds writes by significant amount.
MongoDB is very flexible and it is a blessing and a curse. It will store any data you provide. By default there is no validition you setup validation rules on database or use ODM like Mongoose if you're using NodeJs to help with validation in the application layer.
What is serverless? Serverless is a service where you pay for how much computing power is used, not how much you reserve. Why migrate? Migrate reasons can be several: from security, to cost
Service Level Indicator (SLI) measure of chosen characteristic of the level of service.
Assign only those permissions which are required to get the job done. Also utilise infrastructure as a code (IaC) tool like Terraform to track changes in your infrastructure to prevent unwanted human error and if it happens track down easily.