I just dug out and dusted off my E1 from the archives and decided to try it again. Seems like a small bug must have slipped into one of the last update sent out ages ago (back in 2021).
There is no obvious way to switch home screens, when you switch to the "BuzzTV Media Player" Home screen . I know there used to be a "settings" ICON initially in the all apps screen, but that no longer seems to be there. This only happens when using the "BuzzTV Media Player" Home screen option. The other 3 home screen options works fine. The right arrow only works with "BuzzTV Media Player 2" home screen. I always use the "BuzzTV Modern" one, so never even tested it for a long time (since the first days I got the box back in 2020).
However I did find a small workaround. It's not the most elegant solution, but it will avoid someone having to do a hard reset of the box.
Find yourself a simple USB keyboard (like from a PC). Then plug it into one of the USB ports of the E1. And then hit the "F8" key on the keyboard, which will bring up the side menu, where you can then go to the home screen setting and change home screen theme.
Note to self: Don't use the "BuzzTV Media Player" home screen theme
Other option/workaround is to use AptoideTV, and install another launcher (I tested with "Projectivity Launcher"). Once installed, launch it. After getting through the basic setups, from the main launcher screen (under TV Apps - first row), you will see "App Installer", "Aptoide TV", "Buzz TV 4" and then "BuzzTV Classic" along with "BuzzTV Media Player" and "BuzzTV Media Player 2". Well, I selected BuzzTV Classic, and it launched the BuzzTV Classic home screen theme, and was able to go into settings and change the default home screen theme back to my "BuzzTV modern". This is an option in case you do NOT have access to a USB keyboard.
I can't speak for BuzzTV themselves, but I'd be surprised if they send out any update to fix this bug, 4 years after the last update. You'll probably have to accept the limitation and bug, and learn to get around it. Simple: don't use the BuzzTV Media player home screen