my touchpad pointer keeps on slowing down

Random slowdowns like that are commonly caused by touchpad sensitivity or the touchpad driver rather than the pointer speed setting itself.

Try this in order:

1. Open Start > Settings > Bluetooth & devices > Touchpad.
2. Lower the touchpad sensitivity if that option is available.
3. If gesture options are enabled, reduce or turn off extra tap, three-finger, or four-finger gestures to rule out accidental input.
4. Test again and check whether the slowdowns stop.

If it still happens, update or reinstall the touchpad driver:

1. Open Device Manager.
2. Look for the touchpad under Human Interface Devices or Mice and other pointing devices.
3. First try updating the driver. The recommended method is Windows Update.
4. If updating does not help, reinstall the touchpad driver through Device Manager. Reinstalling forces the latest driver to download from Windows Update.

Also check whether the problem is limited to the touchpad:

• If an external mouse works normally while the touchpad slows down, that points to the touchpad or its driver.
• Close open apps and restart the PC, because heavy app usage or a recent driver change can affect input performance.

If the issue continues after reinstalling the driver, get the touchpad driver from the laptop manufacturer’s support page and reinstall that version.

References:

• Fix touchpad problems in Windows
• Surface touchpad use and settings
• Troubleshoot problems with your Surface mouse or keyboard
• My mouse has gone crazy - Microsoft Q&A
• Cursor moving randomly - Microsoft Q&A