Unity Character Movement Optimization

I have a playable Unity project but the character-movement scripts are starting to bottleneck the frame rate. I need a C# developer to dive into the current code, profile it, and streamline the logic so the movement feels just as responsive while using fewer CPU cycles.

Scope
• Focus only on gameplay mechanics—specifically the character’s movement controller, collision handling, and related Update/FixedUpdate calls.
• No changes to graphics, loading screens, or other systems.

What I’m after
1. A refactored movement script (or set of scripts) that maintains existing behaviour but runs more efficiently.
2. Before-and-after metrics captured with the Unity Profiler (e.g., average ms per frame, GC allocations).
3. Clear in-code comments plus a brief summary document explaining what was changed and why.

Tech notes
Project is built in the current LTS version of Unity. The codebase is pure C#. I’m comfortable pulling updates from a Git repo or receiving a clean package for drop-in replacement.

Success looks like noticeably smoother movement and reduced spikes when multiple characters spawn. If you have a track record optimising FixedUpdate loops, physics queries, or input handling, I’d love to see it.