Even using the Document Based App template with Xcode 11 and building and running it on the simulator without changing anything all I get is a blank white screen (beta 2 of Xcode and iOS 13) - no document picker. I do have a first gen iPad Pro I put beta 1 and 2 on and on it, I do get the document picker and can open a file. On the iPad, the opened document window appears centered covering about 1/3 the width of the screen rather than covering the entire screen.
I've got other issues with my actual app and trying to open a custom document type but I'll start a new thread for that (https://forums.developer.apple.com/message/366848).
These errors show up in the console when trying it in the simulator (and I just get the blank white screen):
2019-06-20 16:51:33.892103-0400 DocumentBasedApp[21412:8135268] [general] CFLocaleCopyCurrent() failed to look up current locale via 'AppleLocale' and 'AppleLanguages' in user preferences; falling back to locale identifier 'en_US' as the default. Consider checking Console for sandbox violations from this process for reading from preferences, or enabling CoreFoundation debug logging for more information. This will only be logged once.
2019-06-20 16:51:33.998986-0400 DocumentBasedApp[21412:8134344] [Assert] COMPATIBILITY BUG IN CLIENT OF UIKIT: Moving method canvasToolbar from UICanvas to UIWindowScene
2019-06-20 16:51:33.999595-0400 DocumentBasedApp[21412:8134344] [Assert] Registering Canvas Component Class _UICanvasUserActivityManager, please update to Frame Components
2019-06-20 16:51:34.006117-0400 DocumentBasedApp[21412:8134344] [Assert] Calling deprecated SPI on UICanvas. This method and class will dissapear prior to GM
2019-06-20 16:51:34.006281-0400 DocumentBasedApp[21412:8134344] [Assert] Calling deprecated SPI on UICanvas. This method and class will dissapear prior to GM
2019-06-20 16:51:34.006773-0400 DocumentBasedApp[21412:8134344] [Assert] Calling deprecated SPI on UICanvas. This method and class will dissapear prior to GM
2019-06-20 16:51:34.017416-0400 DocumentBasedApp[21412:8134344] [TraitCollection] Class _UISheetPresentationController overrides the -traitCollection getter, which is not supported. If you're trying to override traits, you must use the appropriate API.
2019-06-20 16:51:34.017589-0400 DocumentBasedApp[21412:8134344] [TraitCollection] Class _UIRootPresentationController overrides the -traitCollection getter, which is not supported. If you're trying to override traits, you must use the appropriate API.
2019-06-20 16:51:34.078648-0400 DocumentBasedApp[21412:8134344] [TraitCollection] Class UIPopoverPresentationController overrides the -traitCollection getter, which is not supported. If you're trying to override traits, you must use the appropriate API.
2019-06-20 16:51:34.153183-0400 DocumentBasedApp[21412:8134344] [Assert] Calling deprecated SPI on UICanvas. This method and class will dissapear prior to GM
2019-06-20 16:51:35.250925-0400 DocumentBasedApp[21412:8134344] [TraitCollection] Class UIPreviewPresentationController overrides the -traitCollection getter, which is not supported. If you're trying to override traits, you must use the appropriate API.
2019-06-20 16:51:35.287598-0400 DocumentBasedApp[21412:8134344] [DocumentManager] Failed to get the remote browser View Controller with error (Error Domain=NSCocoaErrorDomain Code=4097 "connection on anonymousListener or serviceListener from pid 21415" UserInfo={NSDebugDescription=connection on anonymousListener or serviceListener from pid 21415})
2019-06-20 16:51:35.288279-0400 DocumentBasedApp[21412:8134344] [DocumentManager] Remote view controller crashed with error: Error Domain=NSCocoaErrorDomain Code=4097 "connection on anonymousListener or serviceListener from pid 21415" UserInfo={NSDebugDescription=connection on anonymousListener or serviceListener from pid 21415}. Trying to relaunch.
2019-06-20 16:51:35.368811-0400 DocumentBasedApp[21412:8134344] [DocumentManager] The view service did terminate with error: Error Domain=_UIViewServiceInterfaceErrorDomain Code=3 "(null)" UserInfo={Message=Service Connection Interrupted}
2019-06-20 16:51:36.385713-0400 DocumentBasedApp[21412:8134344] [DocumentManager] Failed to get the remote browser View Controller with error (Error Domain=NSCocoaErrorDomain Code=4097 "connection on anonymousListener or serviceListener from pid 21416" UserInfo={NSDebugDescription=connection on anonymousListener or serviceListener from pid 21416})
2019-06-20 16:51:36.385933-0400 DocumentBasedApp[21412:8134344] [DocumentManager] Remote view controller crashed with error: Error Domain=NSCocoaErrorDomain Code=4097 "connection on anonymousListener or serviceListener from pid 21416" UserInfo={NSDebugDescription=connection on anonymousListener or serviceListener from pid 21416}. Trying to relaunch.
2019-06-20 16:51:36.440484-0400 DocumentBasedApp[21412:8134344] [DocumentManager] The view service did terminate with error: Error Domain=_UIViewServiceInterfaceErrorDomain Code=3 "(null)" UserInfo={Message=Service Connection Interrupted}
2019-06-20 16:51:37.384143-0400 DocumentBasedApp[21412:8134344] [DocumentManager] Failed to get the remote browser View Controller with error (Error Domain=NSCocoaErrorDomain Code=4097 "connection on anonymousListener or serviceListener from pid 21417" UserInfo={NSDebugDescription=connection on anonymousListener or serviceListener from pid 21417})
2019-06-20 16:51:37.384315-0400 DocumentBasedApp[21412:8134344] [DocumentManager] Remote view controller crashed with error: Error Domain=NSCocoaErrorDomain Code=4097 "connection on anonymousListener or serviceListener from pid 21417" UserInfo={NSDebugDescription=connection on anonymousListener or serviceListener from pid 21417}. Trying to relaunch.
2019-06-20 16:51:37.436966-0400 DocumentBasedApp[21412:8134344] [DocumentManager] The view service did terminate with error: Error Domain=_UIViewServiceInterfaceErrorDomain Code=3 "(null)" UserInfo={Message=Service Connection Interrupted}
2019-06-20 16:51:38.380855-0400 DocumentBasedApp[21412:8134344] [DocumentManager] Failed to get the remote browser View Controller with error (Error Domain=NSCocoaErrorDomain Code=4097 "connection on anonymousListener or serviceListener from pid 21418" UserInfo={NSDebugDescription=connection on anonymousListener or serviceListener from pid 21418})
2019-06-20 16:51:38.381007-0400 DocumentBasedApp[21412:8134344] [DocumentManager] The UIDocumentBrowserViewController view service crashed for too many times in a row.
2019-06-20 16:51:38.432923-0400 DocumentBasedApp[21412:8134344] [DocumentManager] The view service did terminate with error: Error Domain=_UIViewServiceInterfaceErrorDomain Code=3 "(null)" UserInfo={Message=Service Connection Interrupted}
