Launch the game. You will see a new overlay or config file (re4_tweaks.toml). Open that file with Notepad. Look for:
[Mouse]
raw_input = true
mouse_sensitivity = 0.5
Set raw_input = true. Set sensitivity to your preference (0.3 to 0.7 is a good range). Save and close.
You need to find where RE4 is installed on your computer. Download Resident Evil 4 Pc Mouse Support
There are a few variations of the mouse support mod, but the most stable and widely used version is generally hosted on modding sites like ModDB or Nexus Mods.
When you search for "download Resident Evil 4 PC mouse support," you will find shady websites offering "auto-aim bots" or "mouse injectors." Be careful. Launch the game
No legitimate mouse support mod requires you to disable all antivirus protection permanently.
Some users report mouse acceleration or smoothing in the 2023 remake. Here is how to fix that without mods: Set raw_input = true
If you still feel input lag, disable Ray Tracing and set Shadow Quality to Medium—these settings are known to add a few frames of latency.