I want the database to allow arbitrary key-value pairs to be added inside datapoints

[Razpudding]

May sound weird but I don't know yet which data fields will be relevant later and I want the physical maintainers of the system to be able to send any data over to the backend.
I'm thinking of having a "deviceInfo" field which is an array that holds an arbitrary number of key-value pairs.

[Razpudding]

Solved this by making all the top level properties of datapoints mandatory and putting the measurement variables in an optimized string. As the string is not validated against anything (other than it being a String) the way measurement data is structured can be changed without the system being affected.
For instance, the date can be changed from dd-mm-yyyy format to mm-dd-yyyy format within the string without any issues.