Compatibility with other mods (Reshade...) - TheRazerMD/OptiScaler GitHub Wiki

If there is another mod (e.g. Reshade etc.) that uses the same filename (e.g. dxgi.dll), you can create a new folder called plugins and put other mod files in this folder. OptiScaler will check this folder and if it finds the same dll file (for example dxgi.dll), it will load this file instead of the original library.

Another option for Reshade - rename Reshade dll to ReShade64.dll, put it next to Optiscaler and set LoadReshade=true in OptiScaler.ini