This might be usefull :
/organizations/{organizationId}/firmware/upgrades/byDevice
{"serial":"X","name":"X","deviceStatus":"Pending","upgrade":{"time":"2023-03-22T03:00:00.000000Z","id":"X","upgradeBatchId":"X","status":"Pending","fromVersion":{"id":"2394","releaseDate":"2023-01-24T20:42:54Z","shortName":"MS 15.19"},"toVersion":{"id":"2443","releaseDate":"2023-03-20T22:40:20Z","shortName":"MS 15.21.1"}}}]
I can see the scheduled firmware upgrade for my MS switch to 15.19 to 15.21.1 that I have scheduled tonight. However you don't see the user who scheduled it.