Hello DavidPark9830,
Thanks for reaching out to Microsoft Community. I understand how important this feature is for your device.
As per article, when it comes to using the feature, you have nothing to worry as the Battery Smart Charging is always active and turns on automatically to limit battery charging to 80% when it detects your device is plugged in for prolonged periods and/or used at elevated temperatures.
For the other Surface devices that support Battery Smart Charging but don't have an asterisk (*), a battery with a heart icon won’t appear. To fully charge your Surface, you'll need to follow the Battery Smart Charging steps in Surface features to optimize your battery longevity.
Let me know how it goes. Looking forward to your response.