You can navigate to '\Documents\Larian Studios\Baldur's Gate 3\graphicSettings.lsx' and edit that in any standard text editor like Notepad.

Find the following two nodes and just change the value to your laptop's resolution:

Code
                <node id="ConfigEntry">
                    <attribute id="MapKey" type="FixedString" value="ScreenHeight"/>
                    <attribute id="Type" type="int32" value="0"/>
                    <attribute id="Value" type="int32" value="1440"/>
                </node>
                <node id="ConfigEntry">
                    <attribute id="MapKey" type="FixedString" value="ScreenWidth"/>
                    <attribute id="Type" type="int32" value="0"/>
                    <attribute id="Value" type="int32" value="2560"/>
                </node>