Okay, I got it. Now, I can use both ENB and ReShade together.
Solution for me:
my enblocal.ini settings:
EnableProxyLibrary=true //Original value: false. I changed it to "true"
InitProxyFunctions=false //Original value: true. I changed it to "false"
ProxyLibrary=Sweetfx.dll //I renamed dxgi.dll file to Sweetfx.dll (in GTA V root folder) and copy-paste its name here. Name doesn't matter but I wanted to try. The main point is you have to choose the correct dll.