UploadOptions and object attributes

Short Question: is there a way to store small metadata with an object?
The Question asked the other way round: could I use the ContentType-Property for my own Purpose and fill it with application-specific data?
Or could I set the created-date on my own when I upload it?

The Background is: I want to upload files for a specific date. But as I would convert from an existing solution, the date is already in the past. I want to sort the objects after listing them by their date-created. If Setting the created-date on my own is not possible, I could use the contenttype-field. If that Needs to be a true Content type (like “application/json”) this would not work and I would Need app-specific metadata. If that is not possible either, I would Need to extract the created data from the object-data itself what makes it difficult an slow.

Using the object-path for this would be possible but leads to other Problems with their own difficulty.

Thank you!

Closing this one - I think adding the date as part of the path is not the worst idea in my case, so no Need to add additional metadata.