So, one of the main reasons people go to the fan patch is that when a lot of people install this game it just won't open. This is because your xlive.dll is out of date, while the game no longer runs off GFWL it still needs this file to be up to date in order to open it, and the game seems to install an older version.

So, download this xlive.dll https://drive.google.com/file/d/15B-cVbLzTOU1aov5LC-bcOkusGzfZZdX/view?usp=sharing

And place it in here. C:\Program Files (x86)\Steam\steamapps\common\Resident Evil 5

This also avoids some instances where the game will open but in GFWL mode.

If this doesn't work, feel free to ask in the Discord, we have other ways around this :)