Google doc file style not preserved when updated - google-drive-api

Question

I am trying to create a google doc file and fill it with content from html.
Html contains large table element, so to fit it page orientation of google doc must be landscaped. First I am creating google file using Docs API, change its page style to landscape,
and then trying to update this doc file using drive api. But when I do so the style goes back to portrait and html table does not fit to one page.
So basically I want the google doc file to not change its style,
or apply needed style before updating.Is there a way to do that?
My code
//drive service
class DriveService(){
fun getService(): Drive {
private val httpTransport: NetHttpTransport = GoogleNetHttpTransport.newTrustedTransport()
private val jsonFactory = JacksonFactory.getDefaultInstance()
return Drive.Builder(httpTransport, jsonFactory, getCredentials())
.setApplicationName(applicationName)
.build()
}
}
//update google doc file
val fileMetadata = File()
val filePath: java.io.File = ClassPathResource("files/index.html").file
val mediaContent = FileContent("text/html", filePath)
driveService.getService().files().update(
"google doc file id",fileMetadata, mediaContent)
.execute()
The part of code where I create google doc and changing style works fine, so I don't include it here.
UPDATE:
// google credentials
fun getCredentials(): com.google.api.client.auth.oauth2.Credential {
val classPathResource = ClassPathResource(p12FilePath)
val jsonFactory = JacksonFactory.getDefaultInstance()
val httpTransport = GoogleNetHttpTransport.newTrustedTransport()
return GoogleCredential.Builder()
.setTransport(httpTransport)
.setJsonFactory(jsonFactory)
.setServiceAccountId(serviceAccountId)
.setServiceAccountPrivateKeyFromP12File(classPathResource.inputStream)
.setServiceAccountScopes(setOf(DocsScopes.DRIVE_FILE, DocsScopes.DRIVE, DocsScopes.DOCUMENTS))
.setServiceAccountUser(email)
.build()
}