In powerapps, I'm getting the same error saying "name isn't valid" but which is incorrect as it has worked everywhere else?

I'm trying to create two buttons that add or remove a numerical value on a sharepoint list via an overall app. The value is chosen through the use of a slider. No matter what i do, it says "Name isn't valid. 'TotalLeave isn't recognized". The issue is, this exact name works everywhere else. Their are no spelling errors, there are no syntax errors, nothing, or atleast nothing I can see. I cannot for the life of me figure this out. If anyone can help, it would be greatly appreciated.

Code for the add button:

If(
    !IsBlank(
Dropdown_Employee_New
.Selected.EmployeeEmail) && 
Slider_Days
.Value > 0,  // Ensure valid selection and positive days

    Patch(
        EmployeeLeaveBalances,
        LookUp(EmployeeLeaveBalances, EmployeeEmail = 
Dropdown_Employee_New
.Selected.EmployeeEmail),
        {
            TotalLeave: TotalLeave + 
Slider_Days
.Value
        }
    );

    Patch(
        LeaveChangeLog,
        Defaults(LeaveChangeLog),
        {
            EmployeeEmail: 
Dropdown_Employee_New
.Selected.EmployeeEmail,
            EmployeeName: 
Dropdown_Employee_New
.Selected.EmployeeName,
            ChangeType: {
                '@odata.type': "#Microsoft.Azure.Connectors.SharePoint.SPListExpandedReference",
                Value: "Add"
            },
            ChangeAmount: 
Slider_Days
.Value,
            Reason: "Manual adjustment via Add Days",
            ChangedBy: User().Email,
            ChangeDate: Now()
        }
    );

    Notify("Days added successfully!", NotificationType.Success),
    Notify("Please select a valid employee and ensure positive days.", NotificationType.Error)
)

Fixed it. The issue was in the look up.

If(
!IsBlank(Dropdown_Employee_New.Selected) && Slider_Days.Value > 0,  // Ensure a valid employee and positive days

// Update the TotalLeave in EmployeeLeaveBalances
Patch(
    EmployeeLeaveBalances,
    LookUp(EmployeeLeaveBalances, EmployeeEmail = Dropdown_Employee_New.Selected.EmployeeEmail),
    {
        TotalLeave: LookUp(EmployeeLeaveBalances, EmployeeEmail = Dropdown_Employee_New.Selected.EmployeeEmail).TotalLeave 
                    - Slider_Days.Value  
    }
);