How do I slow down the speed when scrolling in excel

Excel for Mac does not provide a separate worksheet scroll-speed setting; reduce the macOS scrolling speed for your mouse or trackpad instead.^1^

Change the scrolling speed

1. Open the Apple menu  → System Settings.
2. Select Mouse if you use a mouse, or Trackpad if you use the MacBook trackpad.
3. Lower the Scrolling speed setting.
4. Return to Excel and test scrolling in the worksheet.
5. Readjust the slider until the movement is comfortable.

This is a system-wide setting, so it also changes scrolling speed in other Mac applications.^2^

For finer movement without changing the Mac-wide setting, use smaller two-finger trackpad gestures or Excel’s arrow keys and scroll bars. Excel officially supports the mouse, trackpad, arrow keys, and scroll bars for worksheet navigation.^1^

References

1. Move or scroll through a worksheet | Microsoft Support
2. Change mouse or trackpad tracking, double-click, and scrolling speed on ...