Hi there, kibi! This is Marc. Thank you for reaching out!
At this time, Smart Charging cannot be permanently disabled through built-in settings, and it may re-enable itself automatically based on system behavior and telemetry. That said, you can try opening the Surface app (preinstalled or available in the Microsoft Store) and look for a Smart Charging section. If available, you may see an option to "Pause Smart Charging," which temporarily allows the device to charge to 100%. Keep in mind this is typically time-limited and will revert after charging or restarting.
Additionally, the system may gradually adapt if you regularly use the battery below 80% and avoid staying plugged in for extended periods. If this feature continues to interfere with your usage, I highly recommend sharing your feedback with Microsoft via the Feedback Hub app (press Windows + F) to request more user control over Smart Charging behavior.
Let me know if this solution works for you.
Best regards,