Hi, I'd first use the DisplayDepth shader to check whether you have actually access to a depth buffer. If the whole screen is black, then there's nothing to work on for the MXAO effect. In that case the culprit is somewhere else (using MSAA can remove the depth buffer in some games, for instance). If you would still like to try your luck with an earlier version of ReShade, you can pull it yourself here from GitHub. Another user friendly pointed me to this possibility a while ago. See reshade.me/forum/releases/4772-4-0?start=180#31437
I'm not sure whether you can actually pull the DLL files there as well, but I still have some earlier ReShade versions saved on my PC if you'd like an earlier version. Note though that you still would have to manually add the correct shader versions, as even an older ReShade installer will get the most recent shaders from the online repository - leaving you with an old DLL and new shaders.