@CarlosFigueira
Content type is a built-in column. When a SharePoint list has "Allow Management of Content Types" enabled, the list then contains a Content Type column automatically. It is a hidden column. You cannot adjust it or see it in list settings.
For me, besides the App that is currently functioning (at an older release level) I set up a test list for testing purposes. That list was very simple. Created the list, set the "Allow management of content types" in the advanced settings. Added two existing site content types to the definition (in my case I chose "Official Notice" and "Message" types)
Back to the new list - created one new list item of type "Official Notice".
Then - went into PowerApps. Connected to the list as a data source. And did some tests:
1) On a button - ClearCollect(testCT, First(myTestList))
Viewed the collection in the collection viewer:

2) On a label - First(testCT).'{ContentType}'.Name
This gives the red X and underlines .Name as an invalid identifier. Name is in the table. Name appears in the "intellisense". But when used, it is invalid.

3) Same label - changed to First(testCT).'{ContentType}'.Id
This provides the full Id of the ContentType which is the correct content type ID in SharePoint

You can see in the first image of the collection, the column is there AND it has the correct information in it, yet it is invalid when used.
I hope that is clear and informative.