To fix the cursor issues on your Galaxy Book Flex α, here are a few potential solutions you can try:

Make sure to update the touchpad driver to the latest version.
Try using an external mouse to see if the issue persists when the touchpad is disabled.

1)Check if any conflicting software or programs are causing the cursor to act erratically and remove them if necessary.
2)Perform a system scan to check for any viruses or malware that may be causing the issue.
3)Run hardware diagnostics to check for any hardware issues with the touchpad or other components of the laptop.

If the problem persists, reach out to Samsung support for further assistance.

Additionally, you've mentioned that the problem occurs when working on specific websites like https://stampaprints.com/ which has a nulled wp-rocket installed. You may want to try disabling any plugins or scripts on the website that may be causing the issue. If the problem persists, reach out to the website developer for assistance.