I have installed macOS Catalina Beta 7 on my MacBook Pro Late 2013. After installing, my Mac prompted me to Restart. While installing the update I noticed that the Apple Logo with the progress bar disappeared. Shortly after, the screen went black and the Macbook froze. I tried a hard reset, but it keeps booting to the "question mark" folder. I tried several boot up methods, clearing NVRAM, starting in safe mode etc, but the Mac simply ignores my keyboard inputs while starting up. My guess is that the Firmware / EFI got corrupt because I can't use any of the key combinations. I can only boot to the question mark folder.
Does anyone have any recommendations or ideas? Thanks in advance and sorry for my bad English :) !