I wrote 'My educational background is on classical music' and Grammarly suggested correcting it into 'My educational background is in classical music'. I looked up examples on Cambridge Dictionary online and Oxford Learner's Dictionary online. Depending on these exemplary sentences which are not directly about 'educational background', 'background on sth' is correct. But Grammarly suggests 'in' so I'm not sure which one is correct.
An example from OALD
Our reporter can now provide more background on this story.
An example from Cambridge Dictionary
Can you give me some background on (= information about the conditions that existed before) the situation?